Nevus comedonicus syndrome: A systematic review of the literature.

Nevus comedonicus (NC) syndrome is a condition first identified in 1978. The cause of NC syndrome has been recently proven to be a gain-of-function, mosaic postzygotic mutation of the NEK9 gene. A systematic review of the literature retrieved 43 well-established cases of NC syndrome reported so far. Three morphological variants of NC in NC syndrome emerged: (a) the more common, predominantly comedonal type; (b) "Selhorst type"; and (c) "atrophoderma vermiculatum" type. NC syndrome is mainly associated with ocular, skeletal, and neural abnormalities, most typically ipsilateral congenital cataract and malformations of fingers and toes.