INCONTINENTIA PIGMENTI

Incontinentia pigmenti (IP) is a hereditary syndrome characterized by specific skin lesions occurring mostly during the neonatal period (96% of the cases before 6 weeks of age). These skin lesions have four ste ps of evolution: inflammatory or erythemato-bullous stage (very often associated with peripheral blood hyper-eosinophilia), proliferative or verruco-lichenoid stage, pigmentary or terminal stage caracterised by ''fountain'' or ''firework'' features (with a picture of pigmentary i ncontinence at histological examination), sometimes there is a fourth stage referred to as ''involutive''. Ocular and neurological involveme nt is the main determinant in the prognosis. Eye lesions include corne al flecks, cataracts, uveitis or optical atrophy with retrolental fibr oplasia. The neurological involvement includes pyramidal syndrome, cer ebral ataxia, microphalia, and mental retardation. The disease has mai nly an X-linked dominant transmission and is usually lethal for males. Rare cases are observed in boys, some being associated with Klinefelt er syndrome. Research is ongoing to identify the IP gene on the X chro mosome. In the familly form of IP, the gene has been located on chromo some Xq(28), which allows prenatal diagnosis using trophoblast biopsy.