Unstable pre-mutation may explain mosaic disease expression of incontinentia pigmenti in males.
Mosaic skin lesions following the lines of Blaschko are found in boys affected by incontinentia pigmenti (IP). For an X-linked gene defect, this is rather surprising. To explain the mosaic disease expression of IP in males, we propose that the disease is caused by an unstable pre-mutation, which normally remains silent in males during early embryogenesis. Occasionally "silencing" is incomplete and gives rise to clinical manifest IP reflecting a mosaic state of alleles with the full and the pre-mutation in the same patient. This model can account for mother-to-son transmission of IP and for disparate phenotypes in monozygotic female twins.
Traupe
H
H
Department of Dermatology, University of Münster, Germany.
Vehring
K H
KH
D002648:Child; D008040:Genetic Linkage; D006801:Humans; D007184:Incontinentia Pigmenti / Q000235:genetics* / Q000473:pathology; D008297:Male; D009030:Mosaicism; D009154:Mutation; D014960:X Chromosome