Late-onset familial onychodystrophy heralding incontinentia pigmenti.

Sir, Incontinentia pigmenti (IP) is an X-linked dominant trait that is intrauterine lethal for males. The disorder is caused by NEMO mutations involving the NFkB activation pathway (1). It is characterized by linear skin lesions and various defects of the central nervous system, the teeth and the eyes. The cutaneous lesions are arranged along the lines of Blaschko, reflecting functional X-chromosome mosaicism (2). Because the diagnosis can now be confirmed or excluded by molecular analysis (1), it is possible to ascertain cases showing a rather mild or atypical involvement. In the present family, nail changes acquired during adulthood were a clue to recognizing two cases of IP.