Clinical Observations on Phenylketonuria

Abstract

THE DISEASE phenylketonuria (PKU) was described over 30 years ago, 1-4 but treatment aimed at preventing the neurologic sequellae of the disease is recent. 5-12 Institution of a phenylalanine-restricted diet mitigates or actually seems to prevent the occurrence of mental retardation when the diagnosis is made in early infancy. 13-17 The recent development of screening programs 18-21 to detect PKU, utilizing techniques applicable to the newborn nursery, has provided the clinician an unusual opportunity to obviate or minimize the occurrence of mental retardation in affected infants. On the basis of case finding in newborn screening programs the estimate of the incidence of PKU has been doubled from one case in approximately 20,000 births to one in 10,000 births. Some questions have been raised as to whether all of the cases thus detected are truly classic PKU cases. 22,23 On the basis of the evidence thus far presented it would appear