De Novo incontinentia pigmenti in female twins.

The cutaneous lesions of incontinentia pigmenti classically evolve in stages, beginning with erythematous vesicular rash and bullae, followed by verrucose lesions, with an eventual macular pattern of splashed or whorled hyperpigmentation. We describe female twins presenting with the classic form of cutaneous expression. Ophthalmologic examination revealed abnormal vascular proliferations in the peripheral retinas in twin B. Several studies have confirmed linkage of familial incontinentia pigmenti to chromosome Xq28, with the factor VIII gene in Xq28 identified as the locus for incontinentia pigmenti. Two-hundred kilobases proximal to this locus, the gene for NEMO (NF-kappaB essential modulator)/IKKgamma (I kappaB kinase-gamma) has been mapped. We describe herein female twins with incontinentia pigmenti caused by a de novo mutation of this locus, as demonstrated by diagnostic polymerase chain reaction.