The neurological complications in 34 Spanish children with hypomelanosis of Ito are described from the Paediatric Neurology Service, Hospital Infantil La Paz, and La Universidad Autonoma, Madrid, Spain. Most were referred because of mental retardation (65%) and seizures (53%), and the ages at time of the first visit were 2 months to 10 years. Skin lesions, observed within the first year of life in 70% of patients, consisted of hypomelanotic depigmented patches, cafe-au-lait spots, and angiomatous nevi; changes in hair color and alopecia also occurred. Noncutaneous abnormalities, observed in 94%, included macrocephaly, microcephaly, hemihypertrophy, kyphoscoliosis, coarse facial features, and hypertelorism. Autosomal dominant inheritance was demonstrated in some. 
COMMENT. The incidence of this disease was estimated at 1 per 1000 new patients consulting a pediatric neurology service, or 1 per 10,000 unselected patients in a children's hospital. It affects all races, but fair-skinned individuals may require a Woods lamp examination to detect the cutaneous lesions.