RESUMO
Hypomelanosis of Ito [HI] is a syndrome with hypopigmented whorls of skin along the Blascho lines. The old name, Incontinentia pigmentosa achromiance was probably used because HI appears to be the negative image of incontinentia pigmentosa. This disorder is inherited as an autosomal - dominant trait with variable penetrance and the implicated genes are 9q33 and q11-13, Xp11. Chromosomal mosaiscm is believed to be the reason that hypomelanosis of Ito is so varied in phenotype. Hypopigmented skin lesions appear as whorls or streaks on any part of body and tend to progress onto uninvolved areas. The cutaneous lesion is often associated with developmental and neurological abnormalities. Pyramidal tract dysfunction, mental retardation and seizures are common neurological signs. Ophtalmologic disorders are also present