Unrecognized Adult Phenylketonuria

Abstract

Phenylketonuria is rarely suspected in adults of normal intelligence, and its complications can therefore be overlooked. Of four adult siblings with previously unrecognized and untreated phenylketonuria, three have normal intelligence, one being a university graduate. Three phenylketonuric women in the sibship have given birth to nine non-phenylketonuric children, all of whom have varying degrees of intellectual deficit. Two of the adults with phenylketonuria have suffered major psychotic illnesses resulting in their admission to a mental hospital, where they were inappropriately given electroconvulsive therapy and antipsychotic drugs. Our experience, together with that of others, suggests that routine testing of urine with the ferric chloride test early in every woman's first pregnancy could prevent some cases of mental retardation. Similar routine screening of the urine of mentally ill patients might avoid illogical treatment for occasional psychotic adults. (N Engl J Med 289:395–398, 1973)