title: Intellectual performance of 36 phenylketonuria patients and their nonaffected siblings.
abstract: Thirty-six patients with a confirmed diagnosis of phenylketonuria (PKU) were identified and placed on dietary therapy before reaching 121 days of age. These children are currently between 4 and 6 years old, and have been given the Stanford-Binet Intelligence Scale. Subsequently, their normal siblings of closet age were selected as matched-pair controls and were also tested with the Stanford-Binet. The mean age of the PKU sample when tested was 50.0 months, and 50.9 months for the normal controls. The 36 index patients scored a mean IQ of 94 and their nonaffected siblings obtained a mean IQ of 99. This five-point mean difference was significant at the .02 level, and suggests the presence of a minimal intellectual impairment associated with PKU, even when treatment begins early and is rigorously monitored.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D010290:Parents; D010661:Phenylketonurias / Q000175:diagnosis / Q000178:diet therapy / Q000235:genetics*