Effect of Age at Loss of Dietary Control on Intellectual Performance and Behavior of Children with Phenylketonuria

Abstract
We determined the effect on intellectual performance and behavior of the age at which dietary control was lost in 119 10-year-old children with phenylketonuria (PKU) who had started on a diet low in phenylalanine before the age of 65 days. The children's diets were considered to be out of control when their blood phenylalanine concentration persistently exceeded 15 mg per deciliter.