Selective decrease of eumelanin in hypopigmented epidermis of hypomelanosis of Ito.

A Japanese infant had bilateral hypopigmented macules in a whorled or marble-cakelike configuration on her trunk and extremities. Her irides were bluish gray and her hair was dark brown. She had photophobia and macrocephaly with developmental delay. Analysis of peripheral lymphocytes and dermal fibroblasts disclosed a normal chromosomal pattern. A new finding was that the eumelanin content of the hypopigmented epidermis was decreased. We suggest that at least a portion of patients with this disorder have a defect in eumelanogenesis in hypopigmented skin.