Incontinentia pigmenti in identical twins with separate skin and neurological disorders.

Incontinentia pigmenti in female identical twins is reported. The first baby showed the typical pigmentation of incontinentia pigmenti, while the second baby had hydrocephalus (colpocephaly) without pigmentation. They were identical, with a rate of 99.9% in 18 blood-type studies. Virus was not detected and cytogenetic studies proved normal. Both showed peripheral eosinophilia. The individual expressions of Incontinentia pigmenti in these identical twins were separated into cutaneous lesions and lesion of the central nervous system (intra-uterine hydrocephalus). Cutaneous lesions developed after birth. Twins with Incontinentia pigmenti are extremely rare and in this family showed different expressions of this disease in space and time.