In certain mental deficiencies an association has been established between the mental defect and a genetically determined biochemical abnormality. For instance, in the phenylketonuric person there is a specific biochemical defect, with the mode of inheritance well known; in others, e. g., the Mongoloid patient, a biochemical defect may be present and the question of inheritance is still debated. Though patients with known biochemical defects constitute only a small portion of all the mental defectives, the number of specific syndromes identified is increasing as the result of continuing research. This rapidly expanding knowledge warrants a summary, with a hope that it will stimulate clinical search for additional patients and entities.In those conditions where the biochemical abnormality is well understood, the basic mechanism is a genetically determined defect in enzyme function, which manifests itself in deviant metabolism of a specific nutrient or substrate. Our classification is in accordance with
WRIGHT SW, TARJAN G, LIPPMAN RW, PERRY TL. Etiologic Factors in Mental DeficiencyErrors of Metabolism That May Lead to Mental Deficiency. AMA Am J Dis Child. 1958;95(5):541–562. doi:10.1001/archpedi.1958.02060050545013
Customize your JAMA Network experience by selecting one or more topics from the list below.