Postzygotic mosaicism and incontinentia pigmenti in male patients: molecular diagnosis yield

Incontinentia pigmenti (IP, MIM 308300) is an X-linked dominant genodermatosis caused by the more frequently occurring (80% of cases) deletion mutation Δ 4-10 on IKBKG gene, located on chromosome Xq28. Incontinentia Pigmenti is generally lethal in male fetuses, while heterozygous females survive owing to functional mosaicism.1 Two potential mechanisms have been proposed to explain the survival of male patients with IP carrying IKBKG mutation: (1) abnormal karyotype, i.e. 47, XXY Klinefelter syndrome; (2) more frequently postzygotic mosaicism for IKBKG mutation.2 Detection of postzygotic mosaicism is dependant of tissue sampling localization and percentage of mutated cells in the sample. This article is protected by copyright. All rights reserved.