Cortical visual impairment in hypomelanosis of Ito.

Hypomelanosis of Ito is a multisystem disorder that is thought to be due to chromosomal mosaicism. The authors report a case of cortical visual impairment in an infant diagnosed as having hypomelanosis of Ito. Cortical dysplasia was evident on magnetic resonance imaging and its presence in key areas of the visual pathway may explain the patient's cortical visual impairment.