Disorders of Amino Acid Metabolism and Mental Retardation

Abstract

Early in the twentieth century, the progress made in organic chemistry and in genetics came at a propitious time because a number of observations were made by astute physicians which advanced the concept that certain diseases occurred in families and were characterized by excretion of unusual chemicals in the urine. Garrod (1909) deservedly is credited with recognizing that an “inborn error of metabolism” was a distinct medical entity. In the sixty or more years since these cases were first described, substantial data have been provided that amino acids, carbohydrates and some lipid components are all involved in abnormalities seen in humans. This literature has been reviewed by Hsia, 1966 and by Stanberry, Wynngarden and Fredrickson, 1970. Many of these disease states have, as part of their clinical presentation, some associated brain involvement.