1 Joseph P. Kennedy, Jr. Laboratories, Department of Pediatrics, University of Wisconsin Medical Center, Madison, Wisconsin
Four educable mentally retarded nonphenylketonuric children were born to a mentally normal hyperphenylalaninemic female whose plasma phenylalanine levels averaged 16 mg/100 ml. Growth was not retarded in three of the children. All were born with head circumferences below two standard deviations from the normal, but these approached normal during their subsequent growth. The children did not appear to differ significantly from other educable retarded children in height or learning ability. No unusual personality pattern was seen in the children, and although each child had minor congenital anomalies, these were not the same in all the children. It is suggested that maternal phenylalanine levels as low as 16 mg/100 ml can cause mental retardation in offspring.
Submitted on October 23, 1970