Inherited defects of biotin metabolism.

Abstract

Biotin is the cofactor of the 4 biotin-dependent carboxylases (propionyl-CoA carboxylase, 3-methylcrotonyl-CoA carboxylase, pyruvate carboxylase, acetyl-CoA carboxylase), which play a key role in vitally important pathways in protein, lipid, and carbohydrate metabolism in man. Since biotin is present in many foodstuffs and required only in trace amounts, acquired deficiency of this vitamin is extremely rare in man. In 1971 the first report of an inherited biotin-responsive disorder was published by Gompertz et al. [1]. The infant suffered from 3-methylcrotonylglycinuria, severe metabolic ketoacidosis, vomiting and seizures, and improved clinically and biochemically with biotin therapy. Deficiency of each of the biotin dependent carboxylases, i.e., multiple carboxylase deficiency (MCD), was demonstrated in his cultured fibroblasts.