Genodermatoses

Question 1

Birt-Hogg-Dube Syndrome

Answer 1

Gene: BHD gene (folliculin)
Key Features: often presents >25yo
+Skin (fibrofolliculomas, trichodiscomas, and acrochordons)
+Kidney (renal cell carcinoma; often bilateral)
+Lung (recurrent spont. pnmothrx, lung cysts, bullous emphysema

Question 2

Cowden Syndrome

Answer 2

Gene: PTEN (autosomal dominant)
Key Features: often presents 2nd/3rd decade
+Skin (tricholemmomas, oral papillomas, acral keratotic papules, palmoplantar translucent punctate keratoses, lipomas)
+Breast (adenocarcinoma, fibroadenomas, FCD)
+Thyroid (goiter, follicular adenocarcinoma, thyroglossal duct cysts)
+GI (hamartomatous polyps, usually benign)
+GU (ovarian cysts)
+Craniofacial/Sk (adenoid facie, high arched palate, craniomegaly, kyphoscoliosis)

Question 3

Gardner Syndrome

Answer 3

Gene: APC (autosomal dominant)
Key Features: often presents infancy to early childhood
+Skin (epidermoid cysts, fibromas)
+MSK (osteomas- maxilla, mandible, other skull bones)
+GI (polyposis w/ predisp to malignant adenoCa, desmoid tumors)
+Eyes (congenital hypertrophy of retinal pigment epithelium CHRPE)
+Teeth (odontomas, supernumerary teeth)

Question 4

Peutz-Jeghers Syndrome

Answer 4

Gene: STK11 (autosomal dominant)
Key Features: birth to first few years of life
+Skin (pigmented macules, esp on perioorificial skin, lips, buccal mucosa, digits, nails, palms, soles; may fade with time except buccal)
+GI (hamartomatous polyps; SI>LI; intususception, GI bleeding, anemia, adenoCa)
+Neoplasm (increased frequency of ovarian, breast, and pancreatici carcinoma)

Question 5

Muir-Torre Syndrome

Answer 5

Gene: MSH1, MSH2 (autosomal dominant); DNA repair genes
Key Features: 5th/6th decade
+Skin (multiple sebaceous tumors: adenomas, carcinomas, hyperplasias, epitheliomas, BCC w/ sebaceious diff, KAs)
+Neoplasms (colon adenoCa, other GI, GU, lung, breast, and hem malignancies)

Question 6

CHILD Syndrome

Answer 6

Congenital Hemidysplasia
Gene: NSDHL (X-linked dominant)
Key Features: birth/1month
+Skin (unilateral ichthyosiform erythroderma with sharp midline cutoff involving trunk and limbs; +/- linear or segmental involvement on contralateral side; lesions improve with age but may persist in skin folds—ptychotropism)
+Hair (ipsilateral alopecia)
+Nails (severe dystrophy)
+MSK (hypoplasia to agenenis of limbs ipsilateral to ichthyosis; other ipsilateral bones may be involved; +/- stippled epiphyses_
+Internal Organs (hypoplasia to agenesis of organs below ichthyosis.. including CNS, CV, renal, and GU)

Question 7

Netherton Syndrome

Answer 7

Gene: SPINK5 encoding LEKT1, a serine protease inhibitor (autosomal recessive)
Key Features:
+Skin (Birth- generalized erythema and scaling with secondary hypernatremia; failure to thrive; Late infancy- migratory erytehmatous polycyclic serpiginous plaques with double-edged scale along the margins—ILC—; atopic dermatitis; seborrheic-like scale and erythema on face, scalp, eyebrows)
+Hair (trichorrhexis invaginata; short, sparse)
+Immunology (anaphylaxis to food)

Question 8

KID Syndrome

Answer 8

Gene: GJB2, encoding connexin 26 a gap junction protein in epidermis and cochlea (autosomal dominant and recessive)
Key Features:
+Skin (generalized mild hyperkeratosis with follicular plugging; erythematous keratotic plaques on face, extremities>trunk; palmoplantar keratoderma with stippled surface; recurrent bacterial/fungal infections; SCC of skin, tongue not rare)
+Hair (alopecia)
+Nails (dystrophic)
+ENT (nonprogressive sensorineural deafness)
+Eyes (progressive bilateral vascularized keratitis; secondary blindness may occur)