Isovaleric Acidemia

Abstract

A NEW disorder of leucine metabolism has recently been discovered in 2 siblings who presented a unique clinical syndrome. Previously, 2 other pathologic states that are etiologically associated with abnormalities of branched-chain amino acid metabolism have been recognized in man (Fig. 1). The first, hypervalinemia,^{1 , 2} is due to a deficiency of the enzyme that converts valine to its corresponding keto acid. The second disorder, maple-syrup-urine disease (branched-chain ketonuria),^{3 , 4} results from a defect in the oxidative decarboxylation of leucine,⁵ as well as isoleucine and valine. The deficiency of the decarboxylase leads to an accumulation of the branched-chain amino acids and their . . .