[Genetic interpretation of linear skin abnormalities].

For the linear distribution of congenital skin lesions, modern genetics offers several explanations. Localized linear nevi may be due to somatic mutations. Generalized linear nevi may be the result of early somatic mutations or of gametic half chromatid mutations. The generalized linear patterns of incontinentia pigmenti, focal dermal hypoplasia and sex-linked chondrodysplasia punctata may be explained by functional X-chromosome mosaicism. The same mechanism may account for a peculiar striation of bones observed in focal dermal hypoplasia. Exceptional cases of incontinentia pigmenti and focal dermal hypoplasia in males may be due in part to the gonosome constitution XXY, and in part to gametic half chromatid mutations.