Description Biochem/physiol Actions Isovalerylglycine is a byproduct of the catabolism of the amino acid leucine. Accumulation of isovalerylglycine occurs in Isovaleric Acidemia (IVA), an autosomal recessive disorder caused by mutations in the isovaleryl-CoA dehydrogenase gene. The deficiency of this enzyme in the metabolism of leucine leads to the accumulation of a series of isovaleryl-CoA metabolites, such as isovalerylglycine (IVG).