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

Abstract

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.

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