INTELLIGENCE OF THE UNIDENTIFIED PHENYLKETONURIC CHILD

Abstract

Data are presented which confirm the clinical observations of most workers in the field who are convinced that untreated PKU [phenyl-ketonuria] causes severe mental retardation. The proportion of phenylketonurics without mental retardation was low. This agrees with earlier studies using urine tests which show that no PKU was present among 18,220 normal individuals, and that many fewer cases of PKU were present among morons and educationally subnormal individuals than among those who were severely retarded.