101 - 200

Question 1

A patient with a white, spongy overgrowth of the buccal mucosa that has passed in an autosomal dominant fashion is most likely related to a mutation in which of the following?
1 Keratin 1/10
2 Keratin 6b/17
3 Keratin 4/13
4 Keratin 6a/16
5 None of these options are correct

Answer 1

This description is most likely a white sponge nevus, an autosomal dominant defect in keratin 4/13. Keratin 1/10 is mutated in epidermolytic hyperkeratosis and Unna-Thost PPK, Keratin 6a/16 in pachyonychia congenita type I, and keratin 6b/17 in pachyonychia congenita type II.
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Question 2

A child presents with sparse, short hair and sensorineural deafness. On microscopic examination of the hair, pili torti is noted. Which of the following syndromes is the most likely diagnosis?
1 Bjornstad syndrome
2 Menkes kinky hair syndrome
3 Argininosuccinic aciduria
4 Trichothiodystrophy
5 None of the options are correct

Answer 2

Bjornstad syndrome is the most likely diagnosis. This rare syndrome (~25 cases) is autosomal recessive. Findings are of deafness and pili torti. The most common hair finding in Menkes syndrome is pili torti, but it is not associated with hearing loss. Argininosuccinic aciduria is associated with trichorrhexis nodosa and has no associated hearing loss.
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Question 3

Menke’s kinky hair syndrome is caused by a defect in:
1 Mitochondrial gene
2 DNA helicase
3 Gap junction protein
4 Copper Transporting ATPase
5 Proto-oncogene

Answer 3

Menke’s kinky hair syndrome is an x-linked recessive disorder caused by a mutation at Xq12 leading to defective intestinal copper transport.
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Question 4

What finding is seen on brain imaging of patients with Papillon-Lefevre Syndrome?
1 Tram track calcifications
2 Calcification of the falx cerebri
3 Calcification of the hippocampus
4 Calcification of the dura
5 Agenesis of the corpus callosum

Answer 4

Pappilon Lefevre Syndrome is an autosomal recessive syndrome characterized by transgredient PPK and periodontitis. There is a defect in cathepsin C. One sees dural calcification at the tentorium and choroid attachments. Tram track calcifications are seen in STurge-WEber. CAlcification of the falx cerebri and agenesis of the corpus callosum is seen in basal cell nevus syndrome. Hippocampal calcification is seen in lipoid proteinosis.
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Question 5

Odontogenic cysts and palmoplantar pits are seen in:
1 Gardner�s syndrome
2 Gorlin Syndrome
3 Bloom�s Syndrome
4 Goltz Syndrome
5 Refsum syndrome

Answer 5

Gorlin syndrome (Basal Cell Nevus Syndrome)is an autosomal dominant disorder due to a defect in the PTCH gene whose function normally inhibits �SMOOTHENED� signaling. Odontogenic cysts and palmoplantar pits are characteristic features, in addition to multiple basal cell carcinomas. Other features include: frontal bossing, kyphoscoliosis, calcification of falx cerebri, hypertelorism, ovarian fibromas and rarely mental retardation.
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Question 6

Which of the following elastic tissue diseases demonstrates calcified elastic fibers?
1 Cutis laxa
2 Marfan syndrome
3 Anetoderma
4 Pseudoxanthoma elasticum
5 Buschke-ollendorf syndrome

Answer 6

Pseudoxanthoma elasticum is usually an autosomally recessive inherited condition due to a defective transport protein, ABCC6. The clinical manifestations of the disease arise from fragmented and calcified fibers of the skin, eyes and arteries. Patients may have yellow papules, loose redundant skin, angioid streaks and hemorrhage. Histologically, the hallmark of pseudoxanthoma elasticum is calcified elastic fibers.
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Question 7

A 9 year old boy has sparse, short, brittle hair. A blood test reveals low serum copper. What is the inheritance pattern of this disease?
1 X-linked recessive
2 X-linked dominant
3 Autosomal dominant
4 Autosomal recessive
5 Mitochondrial

Answer 7

Menkes kinky hair syndrome is an x-linked recessive disorder caused by defects in ATP7A, an ATP-dependent copper transporter. It is characterized by pili torti, trichorrhexis nodosa, short, britle hair, lax skin, CNS deterioration, seizures, and tortuous arteries.
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Question 8

In biopsies from blisters in patients with junctional epidermolysis bullosa, the split is found in the:
1 Basal cell layer of the epidermis
2 Lamina lucida
3 Lamina densa
4 Squamous cell layer of the epidermis
5 None of the answers are correct
a Problem

Answer 8

The split seen in junctional epidermolysis bullosa is in the lamina lucida. The other locations can be involved in blistering disease, but not junctional epidermolysis bullosa.

Question 9

A 32 year-old woman is 5 weeks pregnant and is diagnosed with hyperthyroidism. Her doctor gives her a prescription for on methimazole 10 mg PO tid. Which of the following fetal abnormalities could be caused by this exposure?
1 Aplasia cutis congenita
2 Meningocele
3 Encephalocele
4 Spina bifida
5 Dermoid cyst

Answer 9

In-utero methimazole exposures has been linked to aplasia cutis congenita and should not be used in pregnant women. The FDA pregnancy class is D. The other listed options are not linked with maternal methimazole usage.
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Question 10

The combination of gastrointestinal polyposis, nail atrophy, alopecia, generalized pigmentation of skin, and melanotic macules of the fingers is characteristic of which of the following syndromes?
1 Nicolau-Balus syndrome
2 Peutz-Jeghers syndrome
3 Cronkhite-Canada syndrome
4 Cowden syndrome
5 Bannayan-Riley-Ruvalcaba syndrome

Answer 10

Cronkhite-Canada syndrome is a sporadic gastrointestinal polyposis syndrome associated with nail atrophy, alopecia, generalized pigmentation of the skin, and melanotic macules on the fingers.
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Question 11

Which of the following is NOT part of the Carney complex?
1 Peg or conical teeth
2 Cardiac, cutaneous or mammary myxomas
3 Pigmented skin lesions
4 Endocrine abnormalities
5 Primary pigmented nodular adrenocortical disease

Answer 11

Peg/conical teeth are not part of the Carney complex. This is found in incontinentia pigmenti and anhidrotic ectodermal dysplasia. The remaining skin findings are part of this complex sometimes known as NAME syndrome. It consists of multiple, diffuse mucocutaneous lentigines, cardiac and subcutaneous myxomas and endocrine abnormalities may be present. Other findings include: testicular tumors, thyroid disease, primary pigmented nodular adrenocortical disease, psammomatous melanotic schwannomas and hormone-secreting pituitary adenomas.
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Question 12

Mutation in lamin A (nuclear envelope protein) has been found in:
1 Peutz-Jeghers syndrome
2 Buschek-Ollendorf syndrome
3 Progeria (Hutchinson-Gilford)
4 Albright�s syndrome
5 Marfan syndrome

Answer 12

Progeria (Hutchinson-Gilford syndrome) is a sporadic condition characterized by lipoatrophy, sclerodermoid skin, alopecia, nail atrophy, craniomegaly with small face, muscle/bone wasting, and severe premature atherosclerosis resulting in early death. Recent studies have shown that mutations in nuclear envelope protein lamin A is associated with progeria.
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Question 13

Electron microscopic examination of a hair shaft reveals a canal-like groove along the shaft of a triangular-shaped hair. This patient has:
1 Netherton’s syndrome
2 Menke’s Kinky Hair syndrome
3 Spun-glass hair
4 Trichothiodystrophy
5 Bjornstad syndrome

Answer 13

Pili trianguli et canaliculi is also known as Spun-glass hair or Uncombable Hair Syndrome. Netherton patients have trichorexis invaginata, Menke’s kinky hair patients have short, brittle sparse hairs, “tiger tail” hair is seen in trichothiodystrophy, and pili torti is seen in bjornstad syndrome.

Question 14

The treatment for acrodermatitis enteropathica is:
1 Zinc supplementation
2 Iron supplementation
3 Vitamin B1 supplementation
4 Vitamin B12 supplementation
5 Phlebotomy

Answer 14

Acrodermatitis enteropathica is due to a defect in zinc absorption and will respond to zinc supplementation. Iron, Vitamin B1/12 supplementation will not result in improvement in this condition. Findings include periorificial, scalp, and acral dermatitis, scaling, vesicles/bullae, erosions, alopecia, diarrhea and stomatitis.

Question 15

A 16 year-old girl presents with a family history of Gardner syndrome. Her mother is very concerned that her daughter may have the syndrome as it runs in her family and she has many skin complaints. Gardner syndrome has been linked to defects in beta-catenin mediated transcription. Which of the following genes dysfunction is responsible?
1 APC
2 STK11
3 CYLD
4 PTCH
5 ABCC6

Answer 15

APC gene has been associated with defects in beta-catenin mediated transcription. The remaining genes are not associated with Gardner syndrome.
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Question 16

A thirty-year-old woman presents with new progressively worsening headaches. Upon exam, you notice multiple acral keratotic papules and papillomas of the tongue. What malignancy does this patient need to be screened for?
1 colon cancer
2 ovarian cancer
3 breast cancer
4 basal cell carcinoma
5 melanoma

Answer 16

This patient has Lhermitte-Duclos disease, which is a hamartomatous overgrowth of cerebellar ganglion cells. Approximately half of patients have Cowden syndrome. Breast cancer is the correct answer, which affects 25-35% of female patients. Patients can also develop thyroid and genitourinary carcinoma (endometrial, urethral, renal cell, and transitional cell carcinoma of the renal pelvis). Malignant degeneration of hamartomatous colon polyps is rare.
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Question 17

Patients with hemochromatosis are at increased risk for which of the following?
1 Vibrio vulnificus infections
2 Yersenia infections
3 Polyarthritis
4 Generalized metallic-grey hyperpigmentation
5 All of these options are correct

Answer 17

Patients with hemochromatosis have increased intestinal iron absorption leading to systemic iron overload. Signs inclued a generalized metallic-grey hyperpigmentation, koilonychia, alopecia (especially pubic/axillary hair) cardiac failure/arrythmias/heart block, hepatomegaly with crrhosis, diabetes (bronze diabetes), polyarthritis with chondrocalcinosis and are susceptible to Vibrio vulnificus and Yersinia infections.
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Question 18

Which of the following syndromes is associated with markedly increased IgE levels, cold abscesses and a characteristic coarse facies?
1 Wiskott-Aldrich syndrome
2 Chronic granulomatous disease
3 Job syndrome
4 Severe combined immunodeficiency
5 Leiner’s disease

Answer 18

Job syndrome or Hyper IgE syndrome is characterized by these findings. In addition, there is a peripheral eosinophilia, eczematous dermatitis, frequent bronchitis and pneumonia, otitis media and sinusitis. The other listed conditions are associated with immunodeficiency. Wiskott-Aldrich can have eczematous dermatitis and all of these syndromes will have abnormal infections. They do not have markedly increased levels of IgE like Job syndrome.
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Question 19

To help diagnose trichothiodystrophy, which of the following levels are decreased in hairs of affected individuals?
1 Arginine
2 Histidine
3 Phenylalanine
4 Glycine
5 Cysteine

Answer 19

Cysteine and Methionine levels are decreased in hair and nails of patients with trichothiodystrophy. Other sulfur containing amino acids include: Gluthathione, Taurine, and Homocysteine. Testing hairs for decreased sulfur content is an indirect method of determining this. The other listed amino acids are present in normal levels in the hair and nails of trichothiodystrophy patients.
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Question 20

Enchondromas and chondrosarcomas are most strongly associated with which of the following syndromes?
1 Proteus syndrome
2 Osler-Weber-Rendu syndrome
3 Maffucci syndrome
4 Nonne-Milroy disease
5 Blue rubber bleb nevus syndrome

Answer 20

Maffucci syndrome is a sporadic condition caused by defects in the parathyroid hormone/parathyroid hormone related protein type 1 receptor. There are venous malformations of distal extremities, and benign enchondromas that can degenerate into chondrosarcomas.
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Question 21

“Coast of Maine” cafeau lait macules are characteristic of which condition
1 Hypomelanosis of Ito
2 Carney complex
3 McCune-Albright syndrome
4 Gaucher�s syndrome
5 Tuberous sclerosis

Answer 21

McCune-Albright syndrome is a sporadic condition caused by somatic mutations in the Gs subunit of adenylate cyclase. Key clinical features include �coast of Maine� caf� au lait macules, polyostotic fibrous dysplasia, and precocious puberty.
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Question 22

A 4-year old boy presents with generalized white scale. The mother reports that her son was born with a tight membrane enveloping his body. Peripheral blood smear is within normal limits. What is the most likely diagnosis?
1 Congenital ichthyosiform erythroderma
2 Neutral lipid storage disease
3 Lamellar ichthyosis
4 Netherton syndrome
5 Ichthyosis vulgaris

Answer 22

The most likely diagnosis is Congenital ichthyosiform erythroderma. In neutral lipid storage disease, the peripheral blood smear would demonstrate lipid vacuoles in leukocytes and monocytes. Lamellar ichthyosis is characterized by plate-like scale in children/adults. Netherton syndrome is characterized by ichthyosis linearis circumflexa. Ichthyosis vulgaris does not typically present with collodian baby.
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Question 23

A 7 year old boy presents to your office with short and sparse hair. He is also short for his age. A hair mount reveals alternating light and dark bands under polarized light. Which of the following statements is correct regarding this condition?
1 Eyebrows and eyelashes are not affected
2 There is no increased risk of skin cancer
3 Amino acid analysis of hair reveals high sulfur content
4 There is no increased hair fragility.
5 Dark bands represent air

Answer 23

The patient described has trichothiodystrophy, with the hair finding of trichoschisis. These patients have photosensitivity but no increased risk of skin cancer. They also have intellectual impairment, decreased fertility, short stature, and progeria-like facies. Low sulfur content of the hair is found. Eyebrows and eyelashes are also affected. Dark bands in pili annulati, not trichoschisis, are air cavities.
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Question 24

Which of the following laboratory test might prove useful in the diagnosis of Fabry disease:
1 Complete blood count with differential
2 Fasting lipids
3 Urinary sediment exam with polarizing light microscopy
4 Stool guaiac
5 Bleeding time

Answer 24

Patients with Fabry disease have a defect in the alpha-galactosidase A enzyme, leading to an accumulation of glycosphingolipids in all tissues. Although patients are at increased risk for myocardial infrctions and strokes, the serum lipid levels are normal. Ischemic events occur as a result of glycosphingolipid accumulation in endothelial cells leading to swelling. In the brain, strokes occur from direct vessel occlusion or stretching and distention of branches of dolichoectatic parent vessels. Deposits in the kidneys leads to progressive renal failure with urine exam exhibiting proteinuria and birefringent lipid globules (�maltese crosses�) seen with polarizing light microscopy.
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Question 25

Medulloblastoma is seen in which syndrome?
1 Gardner�s syndrome
2 Multiple endocrine neoplasia 2b
3 Muir-Torre syndrome
4 Basal cell nevus syndrome
5 Neurofibromatosis Type 1

Answer 25

Basal cell nevus syndrome is an autosomal dominant syndrome caused by a mutation in PTC gene, which acts in the Sonic hedgehog pathway. Cutaneous manifestations of this genodermatosis include basal cell carcinomas, palmoplantar pits, epidermoids cysts. Other findings include odotogenic cysts, frontal bossing, bifid ribs, calcification of the falx cerebri and medulloblastomas.
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Question 26

Refsum syndrome is due to a deficiency in phytanyl coenzyme A hydroxylase. Treatment for this condition is:
1 Diet low in green vegetables, dairy and ruminant fats
2 Diet high in green vegetables, dairy and ruminant fats
3 Enzyme replacement
4 No treatment is available at this time
5 Avoid phenylalanine

Answer 26

Treatment is with a diet low in green vegetables, dairy and ruminant fats is the treatment of choice for Refsum syndrome. Avoidance of specific amino acids is not helpful.
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Question 27

Epidermal nevus syndromes inheritance pattern is:
1 Sporadic
2 X-linked recessive
3 X-linked dominant
4 Autosomal recessive
5 Autosomal dominant

Answer 27

Epidermal nevus syndrome has many findings, including: sporadic inheritance, nevus unius lateris, capillary malformations, caf� au lait macules, mantal retardation and seizures, deafness, hemiparesis, hemihypertrophy of limbs, kyphoscoliosis and rare solid tumors. A biopsy is helpful to rule out epidermolytic hyperkeratosis. If positive, the patient�s offspring are at risk for generalized epidermolytic hyperkeratosis.
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Question 28

Xeroderma pigmentosum (XP) variant is different than classic XP in which of the following way?
1 Defective DNA nucleotide excision repair of the global genome
2 Defective post-replication repair
3 Increased chromosomal breakage and sister chromatid exchanges
4 Defective DNA nucleotide excision repair of actively transcribing genes
5 Low IgM

Answer 28

XP variant is DNA nucleotide excision repair proficient, but the defect is in post replication repair of DNA. Increased chromosomal breakage and sister chromatid exchanges is found in Bloom�s syndrome, an autosomal recessive syndrome caused by a defect in BLM gene, whose product functions as a helicase. Clinical findings include: Telangiectasias, short stature, malar erythema, recurrent infection, increased frequency of leukemia and lymphoma, normal intelligence. Defective DNA nucleotide excision repair of actively transcribing genes is a feature of Cockayne�s syndrome, an autosomal recessive syndrome with clinical findings including: Cachexia, short stature, pigmentary retinal degeneration, progressive deafness and no increase in neoplasms. Xeroderma pigmentosum has seven different complementation groups (A-G), each associated with a different form of impairment of DNA nucleotide excision repair.
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Question 29

Keratins 1 and 10 are important intermediate filaments in suprabasal keratinocytes. Genetic mutation of these keratins can lead to which of the following disorders?
1 Netherton syndrome
2 Sjogren-Larsson syndrome
3 Pachyonychia congenita type 1
4 Epidermolytic hyperkeratosis / Bullous ichthyosiform erythroderma
5 White sponge nevus

Answer 29

Epidermolytic hyperkeratosis is caused by a genetic mutation in keratins 1 and 10. White sponge nevus is caused by a genetic mutation in keratins 4 and 13. Pachyonychia congenita is caused by a genetic mutation in keratins 6a and 16. Netherton syndrome and Sjogren-Larsson syndrome are not disorders of keratins.
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Question 30

Which of the following hereditary skin disorders is associated with the RAS-ERK-MAPK pathway?
1 Costello syndrome
2 Rothmund-Thompson Syndrome
3 Carney complex
4 Tuberous Sclerosis
5 Griscelli syndrome

Answer 30

Skin disorders associated with the RAS-ERK-MAPK pathway include: Cardio-facio-cutaneous syndrome, Costello, LEOPARD, NF, and Noonan. Rothmund-Thompson is a RecQ DNA helicase defect. Carney complex and Tuberous sclerosis are associated with the cAMP & AMP activated protein kinase pathway. Griscelli syndrome involves defective vesicle trafficking/transport.
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Question 31

Which gene is defective in Wiskott-Aldrich syndrome?
1 WAS
2 CYBA
3 CYBB
4 NCF1
5 NCF2

Answer 31

The WAS gene is defective in Wiskott-Aldrich syndrome. WAS is an Arp2/3 complex interacting protein. The remaining options are genes related to Chronic Granulomatous Disease and are not active in the pathogenesis of Wiskott-Aldrich syndrome.
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Question 32

What is the characteristic radiographic finding in type I Gaucher disease?
1 Enchondromas
2 Osteopoikilosis
3 Melorheostosis
4 Ehrlenmeyer flask deformity
5 Supernumerary vertebrae with extra ribs

Answer 32

The Ehrlenmeyer flask deformity is found in the femoral midshaft as well as aseptic necrosis of the femoral head and widening of the distal femur. Endochondromas are seen in Maffucci syndrome, Osteopoikilosis in Buschke-Ollendorf syndrome, Melorheostosis (linear hyperostosis under affected skin) in linear scleroderma and supernumerary vertebrae with extra ribs in incontinentia pigmenti.
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Question 33

A 12 year old boy presents complaining of pain and stinging of his skin within minutes of going out to play in the park. Examination reveals rare milia of the hands and posterior neck. A diagnosis of porphyria is made. What is the most likely defective gene in this patient?
1 Ferrochelatase
2 Uroporphyrinogen decarboxylase
3 Porphybilinogen deaminase
4 Uroporphyrinogen III synthase
5 Protoporphyrinogen oxidase

Answer 33

Erythropoietic protoporphyria is a relatively common form of porphyria, characterized by photosensitivity. Over time, superficial waxy scars and milia are identified in sun-exposed areas. The defective gene is ferrochelatase. Uroporphyrinogen decarboxylase is mutated in porphyria cutanea tarda. Porphybilinogen deaminase is defective in acute intermittent porphyria. Uroporphyrinogen III synthase is defective in congenital erythropoietic porphyria. Protoporphyrinogen oxidase is mutated in variegate porphyria.
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Question 34

Acropigmentation of Dohi is characterized by:
1 Reticulated pigmentation of the axillae, neck, and groin
2 Linear palmar pits and pigmented macules on volar and dorsal hands and feet
3 Pigmented and depigmented macules on the distal dorsal extremities and face
4 Hyperpigmented macules on the lips and oral mucosa
5 Flaccid, superficial pustules that burst and leave pigmented macules

Answer 34

Patients with Acropigmentation of Dohi (dyschromatosis symmetrica hereditaria) are usually from Europe, India, or the Carribean. They develop pigmented and depigmented macules on dorsal distal extremities and face. This disorder is due to mutation in DSRAD gene. Reticulated pigmentation of the axillae, neck, and groin is seen in Dowling-Degos’ disease. Linea palmar pits and pigmented macules on volar and dorsal hands an feet is seen in Reticulate acropigmentation of Kitamura. Hyperpigmented macules on oral mucosa and lips can be seen in Peutz-Jeghers, Cronkite-Canada, and Laugier-Hunziker syndromes. Flaccid, superficial pustules that burst and leave pigmented macules is seen in transient neonatal pustulosis.
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Question 35

Hyper IgE syndromes are associated with genetic deficiency of which of the following?
1 WASp
2 IL-17 receptor
3 AIRE
4 FOXP3
5 Dock8

Answer 35

To date, three genetic etiologies of hyper IgE syndromes have been identified: STAT3, DOCK8, and Tyk2. All of these hyper IgE syndromes are characterized by eczema, sinopulmonary infections, and greatly elevated serum IgE. However, each has distinct clinical manifestations. Mutations in STAT3 cause autosomal dominant HIES (Job's syndrome), which is unique in its diversity of connective tissue, skeletal, and vascular abnormalities. DOCK8 deficiency is characterized by severe cutaneous viral infections such as warts, and a predisposition to malignancies at a young age. Hyper IgE syndrome associated with Tyk2 deficiency is characterized by nontuberculous mycobacterial infections.
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Question 36

Which of the following is NOT a complication of Kasabach-Merritt Syndrome:
1 Thrombocytopenia
2 CHF
3 Ataxia
4 Disseminated intravascular coagulation
5 Gastrointestinal bleeding

Answer 36

Kasabach-Merritt Syndrome results from platelet trapping due to the presence of a single or multiple large hemangiomas. Hematologic complications include thrombocytopenia, microangiopathic hemolytic anemia, DIC, and acute hemorrhage. The presence of large hemangiomas leads to high output failure (CHF) and can also compress on surrounding structures.
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Question 37

Which of the following syndromes is associated with tricholemmomas?
1 Birt-Hogg-Dube
2 Brooke-Spiegler
3 Bannayan-Riley-Ruvacalba
4 Basex
5 Rasmussen’s

Answer 37

Tricholemmomas are seen in Bannayan-Riley-Ruvacalba syndrome. This is an autosomal dominant condition with macrocephaly, lipomas, hemangiomas, skeletal abnormalities, lymphangioma circupscriptum, angiokeratomas, penile lentigines, acanthosis nigricans, and achrocrodons. There is an increased incidence of breast, thyroid, and GI cancers. Tricholemmomas are also seen in Cowden syndrome.
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Question 38

What is the inheritance pattern of chronic granulomatous disease?
1 Autosomal recessive
2 Autosomal dominant
3 X-linked recessive
4 X-linked dominant
5 Sporadic

Answer 38

Chronic granulomatous disease is inherited in an x-linked recessive manner. There are mutations present in CYBA (a cytochrome subunit), CYBB, and NCF1 & 2 (neutrophil cytosol factors 1 & 2).
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Question 39

The most common ocular association with cutis marmorata telangiectatica congenital is:
1 Cataracts
2 Glaucoma
3 Retinoblastoma
4 Corneal opacity
5 Angioid streaks

Answer 39

Glaucoma is the most common associated eye finding in CMTC patients. Glaucoma is also seen in patients with neurofibromatosis type 1 and Sturge Weber patients.
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Question 40

Which of the following is a feature of Neurofibromatosis type II?
1 Congenital hypertrophy of the retinal pigment epithelium
2 Lisch nodules
3 Juvenile posterior subcapsular lenticular opacities
4 Lester iris
5 Optic gliomas

Answer 40

Neurofibromatosis type II is an autosomal dominant disorder caused by mutations in schwannomin/merlin. Clinical features include cutaneous schwannomas and neurofibromas, bilateral vestibular schwannomas, and juvenile posterior subcapsular lenticular opacities.
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Question 41

The porphyrias are a group of diseases related by abnormal heme synthesis. Which is the only porphyria that is inherited in an autosomal recessive manner?
1 Congenital erythropoietic porphyria
2 Variegate porphyria
3 Porphyria cutanea tarda
4 Acute intermittent porphyria
5 Erythropoietic protoporphyria

Answer 41

The porphyrias are generally inherited in an autosomal dominant manner. Congenital erythropoietic porphyria is unique in being inherited in an autosomal recessive manner. Helpful mnemonic: all porphyrias are autosomal dominant exCEPt one.
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Question 42

Pseudoxanthoma elasticum is caused by mutations in which of the following genes?
1 Fibrillin 1
2 Elastin gene
3 Lysyl oxidase
4 ABCC6 gene
5 Collagen 5

Answer 42

Pseudoxanthoma elasticum is caused by mutations in the ABCC6 gene, which is an ATP-using cell transporter. Elastin and lysyl oxidase mutations cause cutis laxa, fibrillin 1 mutations cause Marfan syndrome, and collagen 5 mutations cause Ehlers-Danlos syndrome.
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Question 43

Primary pigmented nodular adrenocortical disease and psammomatous melanotic schwannomas are characteristic of which of the following syndromes?
1 Hypomelanosis of Ito
2 Carney complex
3 McCune-Albright syndrome
4 Gaucher�s syndrome
5 Tuberous sclerosis

Answer 43

Carney complex is an autosomal dominant disorder caused by mutations in PRKAR1A (protein kinase A regulatory subunit 1-alpha). Key features include cardiac, cutaneous and mammary myxomas, pigmented skin lesions, endocrine abnormalities (pituitary, testicular, thyroid, etc), primary pigmented nodular adrenocortical disease, and psammomatous melanotic schwannomas.
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Question 44

A patient with pseudoherpetic keratitis and a painful PPK would improve with a diet low in:
1 Tyrosine/Phenylalanine
2 Glycine
3 Cytosine
4 Biotin
5 Zinc

Answer 44

Pseudoherpetic keratitis and a painful PPK describes a patient with Richner-Hanhart syndrome (tyrosenemia type II). Treatment is with a diet low in tyrosine and phenylalanine. A diet low in glycine, cytosine, biotin or zinc would not be helpful in this syndrome.
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Question 45

Collagen III is mutated in which type(s) of Ehlers-Danlos syndrome (EDS)?
1 All of the answers are correct
2 None of the answers are correct
3 Benign Hypermobile (type III)
4 Vascular (type IV)
5 Periodontitis (type VIII)

Answer 45

Collagen III is mutated in all three types of EDS listed. Benign hypermobile type EDS is associated with hypermobile joints and is autosomal dominant (AD) in transmission. Vascular type EDS is associated with arterial and visceral rupture leading to early death, and visible venous patterns. It is transmitted autosomal recessive (AR) or AD. Periodontitis type EDS is associated with mild EDS symptoms and periodontitis.
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Question 46

Which of the following syndromes is characterized by follicular atrophoderma, hypohidrosis, hypotrichosis and multiple basal cell carcinomas?
1 Bazex syndrome
2 Rombo syndrome
3 Rasmusen syndrome
4 Gorlin syndrome
5 Incontinentia Pigmenti

Answer 46

Bazex syndrome has the findings of follicular atrophoderma, hypohidrosis, hypotrichosis and multiple basal cell carcinomas (BCC). Rombo syndrome is associated with BCC and hypotrichosis, but not the other listed findings. The atrophoderma in Rombo syndrome is vermicular, not follicular. Rasmusen syndrome is not associated with BCC.
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Question 47

A 4 year-old boy presents with 2 soft, dark-blue, compressible nodules on his extremities. His mother has noted that these lesions have increased sweating and that they were present at birth. No one else in the family has had similar skin lesions. What step is indicated first to help determine the diagnosis?
1 Stool guiac
2 MRI of the abdomen
3 CBC
4 Immediate referral to a gastroenterologist
5 Biopsy of a skin lesion

Answer 47

Blue rubber bleb nevus syndrome is described above. There are multiple venous malformations on the extremities and trunk, often present at birth to early childhood. The number of these lesions increase with age. The lesions may have increased sweating and can be combined with lymphatic-venous malformations. Skin lesions can be a clue to gastrointestinal venous malformations which can lead to secondary bleeding and anemia. The most reasonable screening test to determine if the patient has GI hemorrhage is a stool guiac. An MRI or complete blood count can be helpful, but are not the best test to start with. A skin biopsy is not indicated. If there is GI blood loss, evaluation by a gastroenterologist is useful.
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Question 48

The NEMO gene is defective in Bloch-Sulzberger syndrome. What other syndrome has been linked with defects in the NEMO gene?
1 Hypohidrotic ectodermal dysplasia with immune deficiency
2 Hypomelanosis of Ito
3 Tuberous sclerosis
4 Waardenburg syndrome
5 Piebaldism

Answer 48

Hypohidrotic ectodermal dysplasia with immune deficiency, is caused by mutations in the NEMO (IKK-gamma gene). As opposed to the X-linked dominant inheritance of Bloch-Sulzberger syndrome (incontinentia pigmenti), this is a X-linked recessive disorder. Hypomelanosis of Ito is sporadically inherited and is not linked with a gene defect. Tuberous sclerosis is autosomal dominant and has been linked to defects in tuberin and hamartin tumor suppressor genes. Waardenburg syndrome has four subtypes, linked with the PAX-3, MITF and SOX10/endothelin-3 receptor genes. Piebaldism is linked to defects in the c-kit protooncogene.

Ocular Features
This is primarily a disorder of skin, teeth, hair, and the central nervous system but 35% of patients have important ocular features. The iris is variably atrophic and has pigmentary anomalies often with posterior synechiae. Nystagmus, strabismus, and limited vision are often present. The retinal vascular pattern is anomalous with tortuosity in some areas and absence of vessels in others. Preretinal fibrosis and retinal detachments may suggest the presence of a retinoblastoma. Cataracts are common in patients who have a retinal detachment and some patients have microphthalmia. The retinal pigment epithelium is often abnormal with various-sized patches of sharply demarcated depigmentation. Cases with uveitis, papillitis and chorioretinitis have been observed and it has been suggested that the observed retinal and choroidal changes result from prior inflammatory disease, perhaps even occurring in utero. There is a great deal of asymmetry in the two eyes.

Systemic Features
Skin changes consisting of erythematous eruptions in a linear pattern are often present at birth and this may be followed by a verrucous stage. The acute, early findings of inflammatory disease eventually subside, ultimately resulting in pigmentary changes that appear in a ‘marbled pattern’ in young adults. Hypodontia and anodontia may be present. Alopecia and CNS abnormalities are found in nearly half of patients. Skeletal and structural deformities are common in patients with severe neurological deficits.

As many as 30% of patients have neurological features which may be present in the neonatal period. Seizures of various types occur in 30% of patients. MRI findings include periventricular and subcortical while matter changes, corpus callosum hypoplasia, cerebral atrophy, and cerebellar hypoplasia.

Genetics
The majority of evidence suggests that this is an X-linked dominant disorder with lethality in males although sporadic cases occur. The mutation occurs as a genomic rearrangement of the IKK-gamma gene, also known as NEMO (IKBKG) located at Xq28. There is evidence from skin cultures that cells with the mutant X chromosome inactivated are preferentially viable. It has been proposed that cells with the mutant bearing X chromosome as the active one are gradually replaced by those in which the normal X chromosome is active accounting for the post-natal course of the skin disease.

**********************************************************

Bloch-Sulzberger syndrome
Incontinentia Pigmenti
Clinical Characteristics
Ocular Features
This is primarily a disorder of skin, teeth, hair, and the central nervous system but 35% of patients have important ocular features. The iris is variably atrophic and has pigmentary anomalies often with posterior synechiae. Nystagmus, strabismus, and limited vision are often present. The retinal vascular pattern is anomalous with tortuosity in some areas and absence of vessels in others. Preretinal fibrosis and retinal detachments may suggest the presence of a retinoblastoma. Cataracts are common in patients who have a retinal detachment and some patients have microphthalmia. The retinal pigment epithelium is often abnormal with various-sized patches of sharply demarcated depigmentation. Cases with uveitis, papillitis and chorioretinitis have been observed and it has been suggested that the observed retinal and choroidal changes result from prior inflammatory disease, perhaps even occurring in utero. There is a great deal of asymmetry in the two eyes.

Systemic Features
Skin changes consisting of erythematous eruptions in a linear pattern are often present at birth and this may be followed by a verrucous stage. The acute, early findings of inflammatory disease eventually subside, ultimately resulting in pigmentary changes that appear in a ‘marbled pattern’ in young adults. Hypodontia and anodontia may be present. Alopecia and CNS abnormalities are found in nearly half of patients. Skeletal and structural deformities are common in patients with severe neurological deficits.

As many as 30% of patients have neurological features which may be present in the neonatal period. Seizures of various types occur in 30% of patients. MRI findings include periventricular and subcortical while matter changes, corpus callosum hypoplasia, cerebral atrophy, and cerebellar hypoplasia.

Genetics
The majority of evidence suggests that this is an X-linked dominant disorder with lethality in males although sporadic cases occur. The mutation occurs as a genomic rearrangement of the IKK-gamma gene, also known as NEMO (IKBKG) located at Xq28. There is evidence from skin cultures that cells with the mutant X chromosome inactivated are preferentially viable. It has been proposed that cells with the mutant bearing X chromosome as the active one are gradually replaced by those in which the normal X chromosome is active accounting for the post-natal course of the skin disease.

Question 49

A triangular-shaped lunula is a characteristic finding in which disease?
1 Darier’s disease
2 Dyskeratosis congenita
3 Epidermal nevus syndrome
4 Incontinentia pigmenti
5 Nail-patella syndrome

Answer 49

Nail-patella syndrome, also called hereditary osteo-onychodysplasia is a rare autosomal dominant condition caused by a defect in the LMX1B gene. It is characterized by triangular lunulae, palmoplantar hyperhidrosis, renal dysplasia, glomerulonephritis, and hyperpigmentation of the papillary margin of the iris, an ophthalmologic finding also known as Lester iris. Other nail findings include micronychia with hemionychia, anonychia, and longitudinal fissures. Bony findings include absent or hypoplastic patella, posterior iliac horns, radial head subluxation, thickened scapulae, and scoliosis. Nail findings in Darier’s disease include red and white longitudinal bands, subungual hyperkeratosis and V-shaped nicking of the distal nail plate. Dystrophic nails with longitudinal ridges, pterygium, and atrophic or absent nails can be found in dyskeratosis congenita. Dystrophic changes of the nails can be seen in approximately 5-10% of patients with incontinentia pigmenti.
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Question 50

Which of the following condition is NOT found in Von-Hippel Lindau syndrome?
1 Connective tissue nevi
2 Bilateral retinal hemangioblastomas
3 Cerebellar/CNS hemangioblastomas
4 Renal cell carcinoma
5 Pheochromocytoma

Answer 50

Connective tissue nevi

Von Hippel-Lindau syndrome is characterized by all the options listed except connective tissue nevi. Other findings include pancreatic cysts/carcinoma and cutaneous capillary malformations of the head and neck and polycythemia.

Question 51

What is the most likely nail findings in a patient who has this autosomal dominant disease with these keratotic papules and cobblestoning of the oral mucosa?
1 Koilonychia
2 Red and white longitudinal bands
3 Melanonychia
4 Half and half nails
5 Pincer nails

Answer 51

Darier’s disease is an autosomal dominant disorder characterized by greasy hyperkeratotic papules. The papules often coalesce into a warty plaque and have a tendency for secondary viral or bacterial infection. The mutation is in calcium ATPase 2A2. The classic nail finding is red and white longitudinal bands with V-shaped nicking.
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Question 52

The syndrome characterized by generalized mild hyperkeratosis, erythematous keratotic plaques, palmoplantar keratoderma, non-progressive sensorineural deafness, progressive bilateral keratitis with secondary blindness is:
1 KID syndrome
2 Vohwinkel syndrome
3 Erythrokeratoderma variabilis
4 CHILD syndrome
5 Refsum syndrome

Answer 52

KID syndrome is described above. It is an autosomal dominant mutation in connexin 26. Vohwinkel syndrome is also a connexin 26 mutation, but is characterized by diffuse honeycombed palmoplantar keratoderma, pseudoainhum, starfish-shaped keratotic plaques over joints and deafness. Erythrokeratoderma variabilis is an autosomal dominant mutation in connexin 31 and 30.3 characterized by erythematous migratory patches, fixed hyperkeratotic plaques and a palmoplantar keratoderma. CHILD syndrome is an X-linked dominant mutation condition due to a mutation in NAD(P)H Steroid dehydrogenas-like protein, lethal in males. Unilateral ichthyosiform erythroderma, limb/visceral hypoplasias are characteristic. Refsum syndrome is an autosomal recessive condition with a mutation in phytanoyl coenzyme A hydroxylase characterized by mild ichthyosis, cerebellar ataxia, peripheral neuropathy, retinitis pigmentosa (salt & pepper) and deafness.
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Question 53

A 3 year old boy has white hair of the central frontal scalp and depigmented symmetrical patches on the knees since birth. No ocular abnormalities or deafness are noted. What is true of this disorder?
1 It is an autosomal recessive disorder of melanocyte development
2 There is typically no progression of depigmented patches
3 Regression of the white forelock has been noted
4 One form of this condition is associated with iris pigmentary abnormalities
5 Results from a mutation in a tumor suppressor gene

Answer 53

The patient in this scenario has piebaldism, an autosomal dominant disorder of pigmentation caused most commonly by dominant negative missense mutations in the KIT proto-oncogene. Piebaldism almost always has no progression of the depigmented patches, and is thought to be a static disoder. One exception was noted in a family with a novel Val620Ala (1859T>C) mutation in the KIT gene where development of new depigmented patches did occur. Regression of the white forelock has been noted in select cases. Piebaldism is thought to be unresponsive to systemic treatments or phototherapy. If the patient presented with either eye abnormalities or deafness, Waardenburg syndrome would be considered in the diagnosis.
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Question 54

Which syndrome is due to a defective secreted mammilian Ly6/uPAR-related protein-1?
1 Netherton’s syndrome
2 Refsum’s syndrome
3 Sjogren-Larsson syndrome
4 Mal de Meleda syndrome
5 Haim-Munk syndrome

Answer 54

Mal de Meleda, also known as keratoderma palmoplantaris transgrediens, is due to a defect in secreted mammilian Ly6/uPAR-related protein or SLURP-1.

Question 55

What is the most common ocular findings seen in this condition?
1 Angioid streaks
2 Phakomas
3 Lisch nodules
4 Bitot’s spots
5 Coloboma

Answer 55

Pseudoxanthoma elasticum, PXE, is an inherited disorder that affects selected connective tissue in some parts of the body. Elastic tissue in the body becomes mineralized, that is, calcium and other minerals are deposited in the tissue. The most common ocular finding is angioid streaks. The other ocular findings are seen in these syndromes: Phakomas is seen in tuberous sclerosis, Lisch nodules in neurofibromatosis, Bitot’s spots in Vitamin A deficiency and coloboma in focal dermal hypoplasia.

Angioid streaks, also called Knapp streaks or Knapp striae are small breaks in Bruch’s membrane, an elastic tissue containing membrane of the retina that may become calcified and crack.[1]

They were first described by Robert Walter Doyne in 1889 in a patient with retinal hemorrhages. A few years later, ophthalmologist Hermann Jakob Knapp called them “angioid streaks” because of their resemblance to blood vessels. From histopathological research in the 1930s, they were discovered to be caused by changes at the level of Bruch’s membrane. Presently, it is believed that its pathology may be a combination of elastic degeneration of Bruch’s membrane, iron deposition in elastic fibers from hemolysis with secondary mineralization, and impaired nutrition due to stasis and small vessel occlusion.

Angioid streaks are often associated with pseudoxanthoma elasticum (PXE), but have been found to occur in conjunction with other disorders, including Paget’s disease, sickle cell anemia and Ehlers-Danlos Syndrome. These streaks can have a negative impact on vision due to choroidal neovascularization or choroidal rupture. Also, vision can be impaired if the streaks progress to the fovea and damage the retinal pigment epithelium.

Question 56

The development of which malignancy is most commonly associated with lymphomatoid papulosis?
1 Non-Hodgkin’s lymphoma
2 Mycosis fungoides
3 Multiple myeloma
4 Immunoblastic lymphoma
5 Waldenstrom’s macroglobulinemia

Answer 56

Lymphomatoid papulosis is a recurrant eruption of unclear etiology characterized by the appearance of red-brown papules and nodules which spontaneously disappear in 3 to 8 weeks. It is notable for histologic features which suggest a CD30 positive malignant lymphoma. There is controversy regarding whether lymphomatoid papulosis (LyP) is a malignant, premalignant or benign condition. The disease may last from months to years and in up to 20% of patients, it may be preceded by, followed by, or associated with another type of cutaneous malignancy. Generally, this is mycosis fungoides, a CD30-positive large T-cell lymphoma or Hodgkin’s disease. Because of this potential risk, long-term follow-up of these patients is required.
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Question 57

Which of the following syndromes is associated with hematologic abnormalities?
1 Sturge Weber disease
2 Klippel-Trenaunay-Parks-Weber
3 Kasabach-Merritt syndrome
4 Blue rubber bleb nevus syndrome
5 Bloom�s syndrome

Answer 57

Kasabach-Merritt syndrome is associated with hematologic abnormalities, such as thrombocytopenia, microangiopathic hemolytic anemia, disseminated intravascular coagulation. The condition develops from platelet-trapping within a large hemangioma, most commonly a kaposiform hemangioendothelioma in the retroperitoneal location.

Question 58

What condition is associated with a mutation in CXCR4?
1 Ataxia telangiectasia
2 Leukocyte adhesion deficiency
3 Chronic granulomatous disease
4 SCID
5 WHIM syndrome

Answer 58

Ataxia telangiectasia is associated with mutations in ATM gene. Leukocyte adhesion deficiency is associated with mutations in the common chain of CD18 which is a beta-2 integrin family member, FUCT1, or KINDLIN3. Chronic granulomatous disease is due to mutations in the NADPH oxidase. SCID is a heterogenous group of genetic disorders due to mutations in Jak-3, IL-7Ralpha, CD45, CD3delta/CD3episilon, RAG1/RAG2, and Artemis (DCLREC1C). WHIM syndrome (wars, hypogammaglobulinemia, infections, myelokathexis) is due to a gain-of-function mutation in CXCR4 which results in the retention of neutrophils in the bone marrow. It is inherited in an autosomal-dominant fashion.
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Question 59

A mentally retarded patient is found to also have a malar rash and downward lens displacement. Another clinical feature might include:
1 Hypertrichosis
2 Short stature
3 Multiple nevi
4 Periodontitis
5 Deep venous thromboses

Answer 59

The above described patient has homocystinuria, an autosomal recessive disorder caused by a deficiency in cystathionine beta-synthase, leading to an accumulation of homocysteine. Clinical features include: malar flush, DVT�s, livedo reticularis, leg ulcers, downward lens displacement, myopia, glaucoma, sparse fine hair, mental retardation, and musculoskeletal anomalies.
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Question 60

Epidermolysis bullosa with muscular dystrophy is caused by mutations in which of the following?
1 Keratins 5 and 14
2 Plectin
3 Loricrin
4 Collagen 7
5 Collagen 17

Answer 60

Epidermolysis bullosa with muscular dystrophy is caused by mutations in plectin.
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Question 61

Which of the following diseases is seen only in females?
1 Griscelli syndrome
2 Piebaldism
3 Hypomelanosis of Ito
4 Incontinentia pigmenti
5 Carney complex

Answer 61

Incontinentia pigmenti (Bloch-Sulzberger syndrome) is an X-linked dominant disease that is lethal in males. There are four stages: vesicular, verrucous, hyperpigmented and hypopigmented. Also seen are peg and conical teeth, eye abnormalities, CNS defects, and alopecia. This condition is caused by mutations in the NEMO gene.
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Question 62

A 45 year old woman with history of uterine fibroids presents with painful firm papules of the left upper arm. Biopsy of one of these lesions reveals smooth muscle fascicles. She notes a history of renal cell cancer in her family. The gene implicated in this syndrome has which of the following functions?
1 Telomere maintenance
2 Involved in the Kreb’s cycle
3 Inhibits mTOR signalling
4 Impairs folliculin function
5 Encodes a deubiquitinating enzyme

Answer 62

The patient scenario describes Reed’s syndrome (multiple cutaneous and uterine leiomyomatosis) characterized by uterine and cutaneous leiomyomas, in addition to papillary renal cell cancer. This autosomal dominant disorder is due to mutations within the fumarate hydratase gene, which catalyses the conversion of fumarate to malate in the Kreb's cycle. It is also thought to act as a tumor suppressor gene. With regards to the other answer choices, telomere maintenance is disrupted in dyskeratosis congenita. The tuberous sclerosis genes hamartin (TSC1) and tuberin (TSC2) inhibit mTOR signalling. Mutations in the FLCN gene, with encodes folliculin (thought to act as a tumor suppressor), cause Birt Hogg Dube syndrome. The CYLD gene, a deubiquitinating enzyme, has been implicated in Brooke-Spiegler syndrome.
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Question 63

Which of the following syndromes is X-linked dominant?
1 Anhidrotic ectodermal dysplasia
2 Dyskeratosis congenita
3 X-linked icthyosis
4 Orofaciodigital syndrome 1
5 Menkes kinky hair syndrome

Answer 63

Orofaciodigital sydrome 1 is an X-linked dominantly inherited disorder caused by a defect in the CXORF5 gene. The rest of the above conditions are inherited in an x-linked recessive pattern.
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Question 64

Which malignancy is associated with Cowden syndrome?
1 Colon cancer
2 Renal cancer
3 Lung cancer
4 Ovarian cancer
5 Basal cell cancer

Answer 64

Cowden syndrome is a autosomal dominant syndome with tricholemmomas, oral mucosal papules, acral keratotic papules, thyroid goiter, GI polyps, and fibrocystic breast disease. Malignant associations include breast, thyroid follicular carcinoma, and colon adenocarcinoma.
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Question 65

Pseudoxanthoma elasticum (PXE) can be transmitted in an autosomal dominant, recessive or sporadic manner. Which of the following genes is mutated in PXE?
1 ABCC6
2 MAN1
3 Collagen III
4 Collagen V
5 Collagen I

Answer 65

ABCC6 is mutated in PXE. Other findings include fragmented and calcified elastin in skin, eyes, arteries. There is the appearance of plucked chicken skin on the flexures and yellow papules on the mucous membranes. Angioid streaks are present in the eye. Other findings include gastric hemorrhage and arterial disease. The others are not involved in PXE.
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Question 66

A teenage female presents with the complaint of “nail fungus”. On exam, she has triangular lunulae, palmoplantar hyperhidrosis, micronychia and an absent patella. Which of the following gene defects is most likely in this patient?
1 LMX1B
2 COL5A1
3 EEC1
4 LKB1
5 NEMO

Answer 66

This patient has nail-patella syndrome. The gene defect is an autosomally transmitted defect in LMX1B. This gene is involved in dorsal/ventral limb patterning and is in close proximit to the COL5A1 gene. EEC1 is defective in ectrodactyly-ectodermal dysplasia-cleft lip/palate syndrome and LKB1 in Peutz Jeghers syndrome.
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Question 67

Bilateral ovarian cystadenomas and parotid monomorphic adenomas are seen in which of the following conditions?
1 Cowden syndrome
2 Proteus syndrome
3 Von-Hippel-Lindau syndrome
4 Noonan syndrome
5 Beckwith-Wiederman syndrome

Answer 67

Proteus syndrome is a sporadic condition caused by postzygotic mosaic mutations in PTEN. Clinical features include subcutaneous lymphovenous malformations, capillary malformations, lipomas, connective tissue nevi of palms/soles, hemihypertrophy, frontal bossing, hyperostoses of epiphyses and skull (esp. external auditory canal), scoliosis, bilateral ovarian cystadenomas, and parotid monomorphic adenomas.
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Question 68

A 11 year-old female patient with hypoparathyroidism is referred to your clinic secondary to chronic mucocutanous candidiasis which is refractory to standard treatments. The patient also has malabsorption and severe chronic diarrhea. You determine that she has autoimmune polyendocrinopathy-candiasis-ectodermal dystrophy syndrome(APECED). What is the gene defect for APECED?
1 XAP101 gene
2 AIRE gene
3 CGI-58 gene
4 ALOX gene
5 PAHX gene

Answer 68

The gene responsible for APECED is the AIRE gene, an autoimmune regulator. The XAP101 encodes dyskerin, a defect in which causes dyskeratosis congenita. A defect in CGI-58 causes Chanarin-Dorfman or neutral lipid storage disease with ichthyosis. Defect in the ALOX genes cause congenital ichthyosiform erythroderma. A defect in the PAHX gene causes Refsum syndrome.
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Question 69

Meleda is an island off the coast of Croatia. Its inhabitants have an increased frequency of a malodorous transgradiens palmoplantar keratoderma in a stocking-glove distribution. This condition is autosomal recessive with a defect in:
1 SLURP1 gene
2 Keratin 1/9
3 TOC gene
4 Loricrin
5 Cathepsin C

Answer 69

SLURP1 (Secreted LY6/UPAR-related protein 1) is defective in Mal de Meleda. Keratin 1/9 are defective in Unna-Vorner/Thost palmoplantar keratoderma, an AD diffuse symmetric non-transgradiens PPK. TOC gene is defective in Howel-Evans syndrome, an AD PPK associated with focal, pressure-related, non-transgradiens PPK and esophageal cancer/oral leukoplakia. Loricrin mutations are seen in Vohwinkel syndrome variant and symmetric progressive erythrokeratodermia. Cathepsin C defects are seen in Haim-Munk syndrome (PPK+periodontitis+acroosteolysis+onychogryphosis) and Papillon-Lefevre syndrome (sharply demarcated transgradiens, stocking-glove PPK+periodontitis+dural calcifications and choroids attachments).
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Question 70

Patients with Russell-Silver syndrome exhibit:
1 Clinodactyly of fifth finger
2 Peg teeth
3 Osteopathia striata
4 Broad thumbs
5 Shortened 4th and 5th metacarpals

Answer 70

Characteristic features of Russell-Silver include short stature, bony asymmetry, triangular facies, clinodactyly of fifth finger, and precocious sexual development with cryptochordism/hypospadias. Broad thumbs are seen in Rubinstein-Taybi and shortened fourth and fifth metacarpals are seen in Turner syndrome. Osteopathia striata is characteristic of focal dermal hypoplasia.
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Question 71

A 2 year old female patient has linear atrophy in a Blasckoid distribution, alopecia, nail dystrophy, abnormal teeth, and colobomas. What is the inheritance pattern of this condition?
1 X-linked dominant
2 X-linked recessive
3 Autosomal dominant
4 Autosomal recessive
5 Mitochondrial

Answer 71

Focal dermal hypoplasia, or Goltz syndrome, is an x-linked dominant condition with a defect in the PORCN gene. It is characterized by linear atrophy in a Blasckoid distribution, alopecia, nail dystrophy, abnormal teeth, and colobomas.
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Question 72

What gene defect would you expect to find in a child with white forelock, dystopia canthorum, and upper limb abnormalities?
1 Pax3
2 MITF
3 SOX10
4 Endothelin-3
5 C-kit proto-oncogene

Answer 72

Waardenburg’s syndrome is characterized by depigmented patches, white forelock, and deafness. Both type 1 and 3 are caused by mutations in Pax3. Type 3 is also associated with limb abnormalities. MITF and SOX10 defects are responsible for types 2 and 4 respectively. C-kit proto-oncogene mutatios are seen in piebaldism.
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Question 73

Deficiency of filaggrin is the strongest known predisposing genetic factor for the development of atopic dermatitis. What is the mode of inheritance of mutations in filaggrin?
1 Autosomal dominant
2 Autosomal semidominant
3 Autosomal recessive
4 X-linked dominant
5 X-linked recessive

Answer 73

Autosomal dominant means that a mutation in a gene on one of the two chromosomes in any autosomal chromosome pair results in disease. Autosomal recessive means that mutations in the same gene on both of the chromosomes in the pair must occur for the disease to occur. Autosomal semidominant means that a mutation in one gene of the autosomal chromosome pair results in a mild version of the disease, while mutations in the gene on both chromosomes results in the full-blown disease. Ichthyosis vulgaris is caused by mutations in filaggrin and inherited in a autosomal semidominant manner. This is the genetic explanation for why the phenotype of ichthyosis vulgaris can vary significantly across individuals.
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Question 74

Which of the following disorders is associated with delayed separation of the umbilical cord?
1 Leukocyte adhesion deficiency type 1 (LAD-1)
2 Immunedysregulation, polyendocrinopathy, enteropathy, x-linked (IPEX)
3 Severe combined immunodeficiency disorder(SCID)
4 X-linked agammaglobulinemia
5 Myeloperoxidase deficiency

Answer 74

LAD-1 manifests as a B2-integrin deficiency and often times presents as at birth with a delayed umbilical cord separation.
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Question 75

Menkes kinky hair syndrome is associated most commonly with which of the following hair abnormalities?
1 Pili torti
2 Trichorrhexis nodosa
3 Trichorrhexis invaginata
4 Pili triangulati et canaliculati
5 None of these options are correct

Answer 75

While pili torti is not exclusively found in Menkes kinky hair syndrome, this is the most common hair abnormality found. Trichorrhexis nodosa can be also seen. Trichorrhexis invaginata is commonly found in Netherton syndrome. Pili triangulati et canaliculati is the finding seen in Uncombable hair syndrome.
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Question 76

Pili trianguli et canaliculi is characteristic of which of the following syndromes?
1 Uncombable hair syndrome
2 Bjornstad syndrome
3 Menkes kinky hair syndrome
4 Leiners disease
5 Netherton’s syndrome

Answer 76

Uncombable hair syndrome is characterized by pili trianguli et canaliculi. On examination of the hair, it is triangular with a canal-like groove runs along the shaft. The clinical findings are that of blond, shiny, “spun glass” hair. It is an autosomal dominant syndrome with no known gene locus. The remaining syndromes do not have this hair finding present.
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Question 77

This form of EB simplex has a defect in actin assembly, not keratin formation.
1 Dowling Meara
2 Weber-Cockayne
3 Koebner
4 Kindler
5 Ogna

Answer 77

Kindler syndrome has been reclassified as a subtype of EB simplex due to congenital blistering being the first symptom. These patients do not demonstrate defects in keratin proteins. Instead, the KIND1 gene defect leads to disruption of actin assembly.
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Question 78

Ichthyosis bullosa of Siemens is a condition characterized by fragile blisters at birth, hyperkeratotic plaques on elbows/knees later in life, and a gene mutation in:
1 Keratin 2e
2 Keratin 5/14
3 Keratin 6a/16
4 Keratin 1/10
5 None of these options are correct

Answer 78

Keratin 2e is mutated in ichythosis bullosa of Siemens. Keratin 5 and 14 are defective in epidermolysis bullosa simplex, 6a/16 in Pachyonychia congenital type I (Jadassohn-Lewandowsky), 1/10 in epidermolytic hyperkeratosis and Unna-Thost PPK.
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Question 79

A child presents with the hair finding seen in the image in addition to brittle nails, keratosis pilaris, abnormal teeth and cataracts. Which of the following abnormalities is the most likely mutated?
1 Keratin 1/10
2 Keratin hHb1/hHb6
3 Keratin 6/16
4 Keratin 6/17
5 Keratin 2e

Answer 79

Keratin hHb1/hHb6 is defective in monilethrix, which is described above. Keratin 1/10 defects are found in epidermolytic hyperkeratosis, K6/16 in inflamed skin and pachyonychia congenita type I, K6/17 in pachyonychia congenita type II and K2e in Ichythosis bullosa of Siemens.
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Question 80

A patient presents with bilateral retinal hemangioblastomas and a capillary malformation on her neck. Which gene mutation is most likely?
1 VHL
2 Endoglin
3 PTH/PTHrP type I receptor
4 VEGF receptor-3
5 MFH1

Answer 80

These findings are most characteristic of Von Hippel-Lindau syndrome. VHL is a tumor suppressor gene which is mutated in this syndrome. Other findings include: renal and pancreatic cysts/carcinoma, pheochromocytoma, and cerebellar/other CNS hemangioblastomas. Endoglin is defective in Osler-Weber-Rendu, PTH/PTHrP type I receptor in Maffucci syndrome, VEGF receptor-3 in Nonne-Milroy disease (hereditary lymphedema) and MFH1 in lymphedema and ptosis syndrome.
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Question 81

Germline KILLIN methylation is associated with which of the following syndromes?
1 Bannayan-Riley-Ruvalcaba Syndrome
2 Proteus Syndrome
3 Cowden Syndrome
4 Birt-Hogg-Dube Syndrome
5 Galli-Galli Disease

Answer 81

Loss-of-function mutations in phosphatase and tensin homolog gene (PTEN) mutations cause 80% of Cowden Syndrome, a rare autosomal-dominant disorder, characterized by high risks of breast, thyroid, and other cancers. Other mechanisms of loss of function such as hypermethylation of the KILLIN gene has been identified in Cowden Syndrome. Bannayan-Riley-Ruvalcaba and Proteus syndrome are associated with PTEN loss-of-function mutations. Birt-Hogg-Dube is associated with loss-of-function mutations in FLCN gene. Galli-Galli Disease is not a malignancy-associated disease and is the result of KRT5 mutations.
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Question 82

Which of the following conditions is worsened by ingestion of lithium?
1 Darier�s Disease
2 Hailey-Hailey Disease
3 Haim-Munk syndrome
4 Hereditary lymphedema (Nonne-Milroy disease)
5 Epidermolytic hyperkeratosis

Answer 82

Patients with Darier�s disease should not be treated with lithium due to its worsening or in some cases unmasking the disease. The mechanism for this is not known. Lithium treatment does not worsen the other listed conditions.
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Question 83

A patient with coarse facies, broad nasal bridge, and extensive eczema might be expected to have which abnormal laboratory value?
1 Hypertriglyceridemia
2 High Copper levels
3 Low Zinc levels
4 High IgE levels
5 Anemia

Answer 83

Patients� with Hyper IgE Syndrome (Job syndrome) have impaired regulation of the IgE function and increased susceptibility to infections. In addition to recurrent cutaneous infections including cold abscesses, patients have widespread eczematous dermatitis, recurrent sinopulmonary infections and typically have coarse facies with broad nasal bridge and a prominent nose.
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Question 84

A BSCL2 gene mutation with the cutaneous findings of generalized lipodystrophy, hyperlipemia, hepatomegaly, acanthosis nigricans, elevated basal metabolic rate and non-ketotic insulin resistant diabetes mellitus are characteristic of which of the following syndromes?
1 Berardinelli-Seip congenital lipodystrophy
2 Familial partial lipodystrophy
3 Bjornstad syndrome
4 All of the answers are correct
5 None of the answers are correct

Answer 84

Berardinelli-Seip congenital lipodystrophy is described above. Familial partial lipodystrophy is characterized by a defect in LMNA and has symmetric lipoatrophy of trunk and limbs with sparing of neck, shoulders, buffalo hump area and genitalia, tuboeruptive xanthomas, acanthosis nigricans and hypertriglyceridemia. Bjornstad syndrome is characterized by pili torti and deafness.
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Question 85

What is the most likely gene mutation in this individual who has migratory patches and fixed plaques as depicted in this picture?
1 Connexin 26
2 Connexin 30.3 and 31
3 Calcium ATPase 2C1
4 Loricrin
5 Keratins 1 and 10

Answer 85

Erythrokeratodermis variabilis is an autosomal dominant disease characterized by transient patches of geographic erythema and fixed hyperkeratotic plaques. The disease is due to gene defects in connexin 30.3 and 31.
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Question 86

Which of the following syndromes are linked to a PTEN gene mutation?
1 Banayan-Zonana
2 Proteus
3 Cowden
4 All of these options are correct
5 Lhermitte-Duclos disease

Answer 86

PTEN gene produces a phosphatase the regulates the cell-cycle and apoptosis, therefore acting as a tumor suppressor gene. Tissues affected by this mutation are those with increased proliferation such as epidermis, the oral and gastrointestinal mucosa, and the thyroid and breast epithelium. All of the syndromes listed have mutations in PTEN.
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Question 87

An infant with a very hoarse cry presents to dermatology. His parents have noted that normal scratches are slow to heal and leave broad scars. White and yellow lesions have been noted on the lips, eyelids, and buccal mucosa. The child has had frequent upper respiratory tract infections. What defective gene is associated with the most likely implicated disease?
1 Extracellular matrix protein-1
2 Collagen III
3 Elastin
4 Tenascin-X
5 Fibrillin-1

Answer 87

The child described most likely has lipoid proteinosis, a rare inherited disease of connective tissues that is inherited in an autosomal recessive manner. The implicated defective protein is extracellular matrix protein-1. Collagen III and Tenascin-X defects are seen in Ehlers-Danlos syndrome. Elastin defects are seen in cutis laxa. Fibrillin-1 defects are seen in Marfan disease.
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Question 88

A 16 year-old girl presents with a family history of Gardner syndrome. Her mother is very concerned that her daughter may have the syndrome as it runs in her family and she has many skin complaints. Gardner syndrome has been linked to defects in beta-catenin mediated transcription. Which of the following ocular finding is diagnostic for Gardner syndrome?
1 Lisch nodules
2 Lester iris
3 Congenital Hypertrophy of the Retinal Pigment Epithelium
4 Angioid streaks
5 Retinal detachment

Answer 88

CHRPE (Congenital Hypertrophy of the Retinal Pigment Epithelium) is the characteristic eye finding for Gardner syndrome. Lisch nodules are seen in Neurofibromatosis I, Lester iris in Nail-Patella syndrome and angioid streaks are present in Pseudoxanthoma elasticum. Retinal detachment is not part of Gardner syndrome.
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Question 89

Dyshcromatosis symmetrica hereditaria (DSH) is a disorder characterized by asymptomatic hypo- and hyperpigmented macules on the face and dorsal extremities. Mutations in which of the following genes is associated with this condition?
1 DKC
2 PTEN
3 ADAR1
4 ERCC4
5 STK11

Answer 89

Dyshcromatosis symmetrica hereditaria (DSH) is a rare autosomal dominant pigmentary disease characterized by asymptomatic hypopigmented and hyperpigmented macules distributed on the face and dorsal extremities. It is most common in patients of Asian descent but has also been reported in patients of European and South American descent. The condition is typically limited to the skin but has been associated in rare instances with neurological deterioration and brain calcificiations. The lesions tend to appear in infancy and childhood and stabilize during adolescence. Mutations in the double-stranded RNA-specific adenosine deaminase gene (ADAR1 or DSRAD) underlie DSH. The ADAR1 protein catalyzes the deamination of adenosine to inosine in double-stranded RNA which is important for alternative splicing or alternations of codons for protein translation. However, the precise mechanism by which these mutations lead to actual disease remain unknown. There are two diseases that are phenoptypically similar to DSH and previously thought to be related. The first is dyschromatosis universalis hereditaria (DUH) which is characterized by a mixture of hyperpigmented and hypopigmented macules that are widespread. DSH can be distinguished from DUH by its localization to the face and distal acral sites. The second disease is acropigmentatio retiticularis (AR, also known as acropigmentation of Kitamura). AR is also characterized by hyperpigmentated macules on the dorsal hands and feet as well as palmar pits. However, in contrast to DSH, it is notably devoid of hypopigmented macules. Suzuki et al. sequenced 20 cases of patients presenting with DSH, DUH, and AR. All patients with DSH demonstrated mutations in ADAR1, however, none of the patients with DUH or AR demonstrated mutations. Based on these studies, they proposed that these diseases are in fact distinct and separate from DSH. There are no effective therapies for DSH. However, it is important to distinguish DSH from other more serious disorders that can present with pigment alterations such as dyskeratosis congenita and xeroderma pigmentosum. Both of these conditions present with photosensitivity and squamous cell carcinomas which are not present in DSH.
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Question 90

A child has ichthyosis and is found to have leukocytes with vacuoles filled with lipids on peripheral smear. She most likely has:
1 Chanarin-Dorfman syndrome
2 Ichthyosis hystrix
3 Naxos disease
4 Ichthyosis bullosa of Siemens
5 Ichthyosis vulgaris

Answer 90

This child has Chanarin-Dorfman syndrome, also called neutral lipid storage disease. This is an autosomal recessive disorder characterized by accumulation of triglycerides in the cytoplasm of leukocytes, muscle, liver, fibroblasts, and other tissues. Patients generally have normal blood lipid levels and a finely scaling ichthyosis. They can also have extracutaneous involvement such as cataracts, decreased hearing, myopathy, and neurologic abnormalities.
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Question 91

The coast of Maine cafe au lait macule is a common finding in which of the following syndromes?
1 Tuberous Sclerosis
2 Neurofibromatosis type I
3 McCune-Albright syndrome
4 Watson syndrome
5 Russell-Silver syndrome

Answer 91

McCune-Albright syndrome is due to a sporadic somatic mutation in Gs subunit of adenylate cyclase. The “coast of Maine” cafe au lait macule is a characteristic finding. Other findings in clude polyostotic fibrous dysplasia and precocious puberty. Tuberous sclerosis, Neurofibromatosis type I, Watson syndrome (pulmonic stenosis and CALM’s) and Russell-Silver syndrome (CALMs, short stature, precocious puberty, cryptorchidism and musculoskeletal/craniofacial defects) all have CALMs as a feature, but not the jagged type seen in McCune-Albright syndrome.
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Question 92

Urticaria pigmentosa is linked to a defect in the c-kit protooncogene. What autosomal dominant skin disease also has been linked to this defect?
1 Piebaldism
2 Hypomelanosis of Ito
3 Waardenburg syndrome
4 Hermansky-Pudlak syndrome
5 Incontinentia pigmenti

Answer 92

Piebaldism is linked to a defect in the c-kit protooncogene. Hypomelanosis of Ito has whorled hypopigmentation, occasional CNS defects, scoliosis and anodontia, a sporadic mutation. Waardenburg syndrome has 4 types, 1-3 are AD, 4 is AR. Type 1 & 3 have defects in PAX-3, 2 in MITF, and 4 in Sox10, endothelin-3 ligand or receptor genes. Hermansky-Pudlak syndrome is AR and most commonly linked to defects in HPS, a lysosomal transport protein and AP3B1, a protein important in endocytic/exocytic sorting. Incontinentia pigmenti is an X-linked dominant syndrome with a defect in the NEMO gene.
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Question 93

A patient with multiple facial trichilemmomas is at risk of which of the following cancers?
1 Basal cell carcinoma
2 Breast carcinoma
3 Acute leukemia
4 Cylindroma
5 Oral squamous cell carcinoma

Answer 93

Cowden syndrome (multiple hamartoma syndrome) is an autosomal dominant disorder caused by mutations in PTEN, a phosphatase that dephosphorylates tyrosine, serine, and threonine. Clinically, there are numerous facial trichilemmomas, oral papillomas, acral keratotic papules, sclerotic fibromas, breast fibroadenomas and adenocarcinomas, thyroid adenomas and adenocarcinomas, and hamartomatous polyps of the gastrointestinal tract.
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Question 94

Findings of dysplastic nevi and melanoma inherited in an autosomal dominant fashion is linked with which of the following?
1 Breast malignancy
2 Thyroid malignancy
3 Pancreatic malignancy
4 Renal cell carcinoma
5 Colon carcinoma

Answer 94

Familial dysplastic nevi/melanoma syndrome is linked with increased risk of pancreatic cancers and astrocytomas. There are no reported increased risks for the other types of cancers listed.
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Question 95

Patients with Hermansky-Pudlak syndrome may experience which of the following systemic complications as a result of their disease?
1 Arteriovenous malformations
2 Pulmomary fibrosis
3 Gastroesophageal reflux disease
4 Aortic stenosis
5 Rectal abscesses

Answer 95

Patients with Hermansky-Pudlak syndrome are tyrosinase positive albinos. In addition to their pigmentary dilution and increased risks for cutaneous malignancies, patients lack platelet granules leading to impaired platelet aggregation (and therefore a bleeding diathesis). There is also a lysosomal membrane defect which leads to the accumulation of ceroid lipofuscion in macrophages within the lung (leading to pulmonary fibrosis), gastrointestinal tract (leading to granulomatous colitis), and heart (cardiomyopathy).
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Question 96

Patients with Darier’s disease are at increased risk for:
1 Kaposi’s varicelliform eruption
2 Melanoma
3 Decreased life span
4 Basal cell carcinoma
5 Lipid abnormalities

Answer 96

Kaposi’s varicelliform eruption is the condition in which viral infection occurs in a patient with a pre-existing chronic dermatitis. Darier’s disease is an autosomal dominant genodermatosis caused by a mutation in ATP2A2 which encodes SERCA2. Cutaneous manifestations of warty, hyperkeratotic papules in a seborrheic dermatitis, which may be infected with HSV or bacteria.
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Question 97

Patients with homocystinuria are deficient in:
1 Alpha galactosidase A
2 Transglutaminase
3 Lysyl oxidase
4 Cystathionine synthetase
5 Steroid sulfatase

Answer 97

Homocystinuria is an autosomal recessive disease caused by a deficiency of cystathionine synthetase. Manifestations of this condition may include mental retardation, marfanoid habitus, malar flush, ectopic lentis, embolic phenomena and leg ulcers.
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Question 98

The gene PTEN (phosphatase and tensin homolog deleted on chromosome ten) is implicated in which of the following syndromes?
1 Cowden
2 Banayan-Riley-Ruvalcaba
3 Proteus
4 All of the options are correct
5 None of the options are correct

Answer 98

Mutations in the PTEN gene are implicated in all three syndromes listed. There are conflicting reports in the literature regarding the linkage of Proteus and PTEN mutations. For further details, see OMIM #176920.
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Question 99

Comma-shaped corneal opacities are characteristic of which type of ichthyosis?
1 Ichthyosis vulgaris
2 X-linked ichthyosis
3 Lamellar ichthyosis
4 Nonbullous congenital ichthyosiform erythroderma
5 Refsum syndrome

Answer 99

X-linked ichthyosis patients have comma-shaped corneal opacities that are asymptomatic yet highly characteristic.
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Question 100

Medulloblastomas are seen in which of the following syndromes?
1 Bazex syndrome
2 Familial cylindromatosis
3 Nicolau-Balus syndrome
4 Birt-Hogg-Dube syndrome
5 Nevoid basal cell carcinomas syndrome

Answer 100

Nevoid basal cell carcinomas syndrome (Gorlin syndrome) is an autosomal dominant condition caused by mutations in the patched gene, which is involved in the hedgehog signaling pathway. Patients develop innumerable BCCs, palmoplantar pits, painful odontogenic jaw keratocysts, frontal bossing, bifid ribs, and calcification of the falx cerebri. Medulloblastomas and ovarian fibromas and fibrosarcomas are associated with this condition.
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