Genetic Disorder

Question 1

Both sexes are equally affected, both sexes transmit to offspring, no skipped generation, every child has a parent with disorder except new or spontaneous mutation

Answer 1

Autosomal dominant (AD)

Question 2

Both sexes are equally affected, both sexes can transmit a copy of mutated gene, and their risk to have affected child is 25%, the disorder may be seen in one or more sibling, not all generations are affected

Answer 2

Autosomal recessive (AR)

Question 3

No male-to-male transmission, only females transmit the disease to their sons, daughters are obligate carriers

Answer 3

X-linked recessive

Question 4

Maternal transmission from egg to zygote; both males and females are affected

Answer 4

Mitochondrial inheritance

Question 5

Hypotonia, upslanted palpebral fissures, epicanthal folds, systolic murmur, single transverse creases in hands, brachydactyly, broad space between the first and second toe

Answer 5

Down syndrome (trisomy 21)

Question 6

Screening for hypothyroidism in cases of Down syndrome is at what age?

Answer 6

Newborn screening after birth, at 6 and 12months, then annually if normal

Question 7

Acute myeloid leukemia (AML) is a higher risk in the patient with Down syndrome at what age?

Question 8

Acute lymphocytic leukemia (ALL) is a higher risk in the patient with Down syndrome at what age?

Answer 8

> 1year

Question 9

Newborn with Down syndrome with no murmur on physical examination

Answer 9

Echocardiography (50% of children with Down syndrome have a cardiac defect)

Question 10

The most common cardiac defects associated with Down syndrome

Answer 10

AV canal defects, ventricular septal defect, atrial septal defect, and tetralogy of Fallot

Question 11

The most common gastrointestinal defects associated with Down syndrome

Answer 11

Duodenal atresia, Hirschsprung disease

Question 12

Newborn with clenched fist with overriding fingers, rocker bottom feet, small head, eyes, and mouth with low-set malformed ears, micrognathia, prenatal and postnatal growth deficiency, hypotonia, and ventricular septal defect

Answer 12

Trisomy 18 (Edward syndrome)

Question 13

Newborn with cleft lip, cleft palate, microcephaly, microphthalmia, cutis aplasia, and postaxial polydactyly

Answer 13

Trisomy 13 (Patau syndrome)

Question 14

A 5-year-old boy with intellectual disability, large hands and feet, long face with large ears, large testicles, and hyperextensible joints

Answer 14

Fragile X syndrome

Question 15

Newborn girl with microcephaly, ocular hypertelorism, prominent glabella, frontal bossing (Greek helmet face), beaked nose, hypotonia, and seizures

Answer 15

Wolf–Hirschhorn syndrome (4p-deletion)

Question 16

Newborn with a cat-like cry, hypotonia, microcephaly, moon face, widely-spaced eyes, down-slanting palpebral fissures, high-arched palate, and wide-flat nasal bridge

Answer 16

Cri du chat syndrome (5p-deletion)

Question 17

Newborn with microcephaly, atresia of the ear canal, deep-set eyes, depressed mid-face, protruded mandible, legs are flexed, externally rotated, and in hyperabduction (frog-like position)

Answer 17

De Grouchy syndrome

Question 18

Newborn with profound hypotonia, small for gestational age, feeding problems, failure to thrive, bitemporal narrowing, thin upper lip, almond- shaped eyes, hypogonadism, bilateral cryptorchidism, and small penis

Answer 18

Prader–Willi syndrome (PWS) (paternally derived deletion 15q11–13)

Question 19

Child with hypotonia, jerky ataxic movement, fair hair, large chin and mandible, inappropriate bouts of laughter, and severe intellectual disability

Answer 19

Angelman syndrome (maternally derived deletion 15q11–13)

Question 20

Child with an intellectual disability, supravalvar aortic stenosis, hypercalcemia, friendly “cocktail party” personality, and strabismus

Answer 20

Williams syndrome

Question 21

The most common cause of hypercalcemia in a child with Williams syndrome

Answer 21

Idiopathic

Question 22

Wilms tumor, Aniridia, Genitourinary malformation, Retardation (intellectual disability), long face, upward-slanting palpebral fissures, ptosis, and a beaked nose, due to the absence of PAX6 and WT1 (Wilms tumor) genes

Answer 22

WAGR syndrome

Question 23

Newborn with Coloboma, Congenital Heart defects, choanal Atresia, growth and Retardation (intellectual disability), GU anomalies (hypogonadism), and Ear anomalies

Answer 23

CHARGE syndrome (gene defect CHD7 on chromosome 8q)

Question 24

Vertebral defects, Anal atresia, Cardiac defects, Tracheoesophageal fistula, and/or Esophageal atresia, Renal anomalies, and Limb defects

Answer 24

VACTERL/VATER association

Question 25

The most common association with VATER/ VACTERL syndrome

Answer 25

Congenital heart defects

Question 26

Jaundice, bile duct paucity with cholestasis, peripheral pulmonary stenosis, butterfly vertebrae, triangular face with a pointed chin, long nose with broad mid-nose, and posterior embryotoxon

Answer 26

Alagille syndrome (20p12)

Question 27

Cleft palate, absent thymus, hypocalcemia, tetralogy of Fallot, interrupted aortic arch, recurrent infection, short stature, and behavioral problem

Answer 27

DiGeorge syndrome (22q11.2)

Question 28

Cleft palate, micrognathia, glossoptosis, respiratory distress (airway obstruction caused by backward displacement of the tongue base), and feeding difficulties

Answer 28

Pierre–Robin sequence

Question 29

Pierre–Robin sequence (cleft palate, glossoptosis, and micrognathia or retrognathia); severe myopia or other ocular abnormalities; sensorineural hearing loss; or skeletal abnormalities including hypermobility, scoliosis, or early arthritis

Answer 29

Stickler syndrome

Question 30

Newborn with a disruptive cleft on the face and amputated digits

Answer 30

Amniotic band sequence

Question 31

Preauricular pits, preauricular tags, microtia, hypoplastic cochlea, hearing loss, branchial fistula, and renal dysplasia or aplasia

Answer 31

Branchio-oto-renal syndrome

Question 32

Newborn with underdeveloped mandibular and zygomatic bones, microtia, stenosis of the external ear canal, down-slanting palpebral fissures, coloboma, and conductive hearing loss

Answer 32

Treacher-Collins syndrome (mandibulofacial dysostosis type 1)

Question 33

Short stature below third percentile, short length of the proximal segment of upper arms and legs (rhizomelic shortening), trident hands, stenosis of the foramen magnum, macrocephaly, flat nasal bridge and mid-face

Answer 33

Achondroplasia

Question 34

The most common cause of death in children younger than 4 years with achondroplasia

Answer 34

Brain stem compression

Question 35

Child, with multiple bruises, blue sclera, recurrent fractures, hyperextensible joints, and had delayed closure of fontanelle

Answer 35

Osteogenesis imperfecta (type I is the most common)

Question 36

Adolescent, tall, the lens is dislocated upward, high-arched palate, pectus carinatum, aortic dilatation, and lumbosacral ectasia

Answer 36

Marfan syndrome

Question 37

Adolescent with hyperextensible skin, hypermobile joints, kyphoscoliosis, easy bruising, skin scarring, mitral valve prolapse, and abnormal capillary fragility test

Answer 37

Ehler–Danlos syndrome

Question 38

Eight café-au-lait spots, freckling of the axilla, Lisch nodules, optic glioma, and pseudarthrosis of the fibula

Answer 38

Neurofibromatosis type I

Question 39

An 18-year-old boy with a family history of eighth cranial nerve masses presents with hearing loss, tinnitus, loss of balance, blurring of vision, and posterior subcapsular lens opacities on eye examination

Answer 39

Neurofibromatosis type II

Question 40

Adolescent presents with facial acne that is not responding to treatment, has ash leaf (hypopigmented macules), facial angiomas (adenoma sebaceum), nail fibroma, pitting of dental enamel, and renal angiomyolipomas

Answer 40

Tuberous sclerosis

Question 41

Infantile spasm is commonly associated with

Answer 41

Tuberous sclerosis

Question 42

Helpful sign to assist in early diagnosis of tuberous sclerosis

Answer 42

Ash leaf spots (hypopigmented macules)

Question 43

Most common cardiac finding in infants with tuberous sclerosis

Answer 43

Cardiac rhabdomyomas

Question 44

Newborn with long eyelashes, hirsutism, low hairline, downward- turned mouth, intrauterine growth restriction (IUGR), thin upper lip, micromelia, and syndactyly

Answer 44

Cornelia De Lange syndrome

Question 45

Child with partial albinism, white forelock, premature gray hair, iris heterochromia, cleft lip, and cochlear deafness

Answer 45

Waardenburg syndrome

Question 46

Child with a history of hypoglycemia and omphalocele at birth, coarse facial features, large tongue, earlobe creases, posterior auricular pits, Wilms tumor, and cryptorchidism

Answer 46

Beckwith–Wiedemann syndrome

Question 47

Infant with macrodactyly, hemihypertrophy, lipoma, hemangioma, soft-tissue hypertrophy, and accelerated growth

Answer 47

Proteus syndrome

Question 48

Newborn large for gestational age, macrocephaly, prominent forehead, hypertelorism, intellectual disability, large hands and feet

Answer 48

Soto syndrome

Question 49

Brachycephaly, frontal bossing, wormian bones, hypoplastic or absent clavicles, delayed eruption of deciduous teeth, and joint laxity

Answer 49

Cleidocranial dysostosis

Question 50

Early fusion of sagittal suture, and the head is long and narrow

Answer 50

Scaphocephaly (the most common type of craniosynostosis)

Question 51

Newborn with craniosynostosis, brachycephaly, strabismus, hypertelorism maxillary hypoplasia, beaked nose, proptosis, syndactyly, single nail, broad thumb

Answer 51

Apert syndrome

Question 52

Craniosynostosis, short stature, deviated nasal septum, malocclusion, malposed teeth, no limb defects

Answer 52

Crouzon syndrome

Question 53

Craniosynostosis, broad thumb and toes

Answer 53

Pfeiffer syndrome

Question 54

Tower or clover-leaf skull due to multiple fused sutures, preaxial polydactyly, obesity

Answer 54

Carpenter syndrome

Question 55

Genetic counseling requires

Answer 55

A specific diagnosis with known inheritance mechanism

Question 56

Indications for obtaining a karyotype: examples

Answer 56

Unusual appearance, multiple congenital anomalies, and/or possible mental disability

Question 57

Child has a routine karyotype that reveals 47, XX+21. Appropriate counseling for the parents is

Answer 57

To explain that their child has Down syndrome due to aneuploidy and that they do not need to have their chromosomes checked

Question 58

Cytogenetic nomenclature for embryonic germ cells from a female fetus with the trisomy form of Down syndrome would be

Answer 58

47, XX+21

Question 59

A couple desires prenatal diagnosis because the woman is 39 years old. They want the safest and most reliable form of prenatal testing

Answer 59

Amniocentesis

Question 60

Child has obesity, compulsive overeating, and underdeveloped genitalia, which make you suspect Prader–Willi syndrome. You recall that FISH testing for a chromosome 15 submicroscopic deletion may be diagnostic. The best approach for obtaining a laboratory diagnosis

Answer 60

Obtain a green-top (heparinized) tube for the harvest of white cells with the indication of routine karyotype, including FISH for microdeletion 15

Question 61

Chorionic villus sampling is performed at which weeks of pregnancy?

Answer 61

10–12 weeks of pregnancy

Question 62

Amniocentesis is performed at which weeks of pregnancy?

Answer 62

12–16 weeks of pregnancy

Question 63

Male with tall stature, speech and language delay, learning disabilities, cystic acne in adolescence, no facial dysmorphology, normal intelligence

Answer 63

47, XYY syndrome

Question 64

Female with tall stature; speech/language delay; learning disabilities; normal intelligence, sexual development, and fertility

Answer 64

47, XXX syndrome “triple X syndrome”

Question 65

Male infant with short webbed neck, low posterior hairline, edema of hands and feet, mild intellectual disability mutation of PTPN11 gene

Answer 65

Noonan syndrome

Question 66

A 10-year-old boy with progressive motor disability, cognitive decline, and psychiatric disturbances; his father had the same condition at age 40 years, died at age of 60

Answer 66

Juvenile Huntington disease (because of CAG trinucleotide repeat expansion, clinical onset can occur in childhood) AD