Hypomelanosis of ito is frequently associated with autism.

Twenty-five children with hypomelanosis of Ito are reported: 10 of them had autism, 3 showed autistic-like features, 1 had previously shown autistic features which had subsequently faded, 2 had disintegrative psychosis. The 9 remaining children were all mentally retarded and 5 of them were more markedly retarded in their speech development. The hypothesis is considered that a dysfunction of melatonin may favour the development of both skin depigmentation and autistic behaviour through an altered production of corticotrophin-releasing hormone and, in turn, of proopiomelanocortin.