Hypomelanosis of Ito: a case report with clinical and ultrastructural data.

Hypomelanosis of Ito (HI) is an uncommon skin disorder characterized by the presence of hypochromic areas associated with visceral abnormalities, the most common being neurological, muscular, skeletal and ocular. The authors describe a typical case of hypomelanosis of Ito in a 7-year-old child. The patient was obese, suffered from scoliosis, flat feet and had a bilateral genu valgus. No neurological, ophthalmological or dental malformations were noted. An electron microscopic study of a hypomelanotic area showed decreased functional activity in the melanocytes, which contained only a few rudimentary cytoplasmatic projections and poorly developed organelles. In addition, there was a reduction in the number of mature melanosomes.