Epidemiologia
- Usually isolated, non-syndromic finding at vertex scalp (where scalp closes in-utero)
Clinical presentation
- Isolated forms
- Vertex skin aplasia
- Membranous Aplasia Cutis or Hair Collar Sign (dark tuff of hair surrounding) → evaluate for underlying CNS anomaly (ectopic brain tissue, dysrrafism)
- Localized aplasia of a limb or trunk
- Rare, possible association with a papyraceous fetus
- Isolated focal facial aplasia
- One or more aplastic lesions, unilateral or bilaterl
- Syndromic forms:
- Adams-Oliver
- Median aplasia of the vertex + cutis marmorata telangiectatic congenita + hypoplasia of the extremities
- Setleis syndrome: bitemporal aplasia cutis
- Forms associated with epidermolysis bullosa
- Congenital absence of skin (Bart syndrome): Epidermolysis bullosa
- Forms associated with various malformative conditions, particularly contiguous cerebromeningeal and skeletal malformations (dysraphism)
- Aplasia and sebaceous/epidermal hamartoma: SCALP syndrome, combining sebaceous hamartoma, CNS malformation, corneal dermoid cyst, nevus)
- Association with genotypic disorders: trisomy 13, deletion of the short arm of chromosome 4, translocation 12q-1q, tetrasomy 12p (Pallister-Killian syndrome), Johanson-Blizzard syndrome, Rapp-Hodgkin syndrome, AEC syndrome, Setleis syndrome (syndromic bitemporal aplasia)
- Forms linked to the use of teratogenic substances, in particular synthetic
antithyroid drugs (carbimazole, methimazole) and valproic acid