Incontinentia pigmenti: multisistemic genodermatosis.

Abstract

Incontinentia pigmenti is an X-linked genodermatosis generally lethal in males; thus, it presents almost exclusively in females. It is caused by a loss-of-function mutation in the IKBKG (inhibitor of kappa polypeptide gene enhancer in B cells, kinase gamma) gene that prevents the NFкβ (nuclear factor kappa-light-chain-enhancer of activated B cells) protein from migrating to the nucleus to begin the transcription of factors that amplify the immune response and prevent apoptosis. Consequently, mutant cells become vulnerable to apoptosis when exposed to cytokines and, in turn, lead to vaso-occlusion and ischemia of tissues, such as the skin, the central nervous system and the retina. Dermatological lesions are characteristic and occur in 100% of patients; they are distributed along Blaschko lines, which follow the pattern of migration of skin cells in embryogenesis. The cutaneous manifestations follow a sequence of four phases since birth: vesicular, verrucous, hyperpigmented and hypopigmented. These lesions are relevant for the disease because they guide the clinician towards the diagnosis. Additionally, they are accompanied by neurological abnormalities, such as seizures, and multiple ophthalmological manifestations, such as retinal detachment. Incontinentia pigmenti patients with no clinically significant ophthalmic or neurological compromise have a good prognosis and a normal life expectancy. The abnormalities present are permanent, which can be a cause of concern for the patients.