The DLD gene has been mapped to 7q31.1 chromosome, where it encodes a mitochondrial enzyme called dihydrolipoamide dehydrogenase. This protein consists of 509 amino acids; and weighs approximately 54 kDa. It is also named the L protein of the mitochondrial glycine cleavage system. It is a component of the three alpha-ketoacid dehydrogenase multienzyme complexes; the pyruvate dehydrogenase complex, the alpha-ketoglutarate dehydrogenase complex, and the branched-chain alpha-keto acid dehydrogenase complex.

DLD is a flavoprotein enzyme that oxidizes dihydrolipoamide to lipoamide. In addition, the DLD enzyme forms a subunit called the E3 component that is shared by several enzyme complexes, including the pyruvate dehydrogenase complex, which plays an important role in converting pyruvate to acetyl-CoA within the cells.

Defects in the dihydrolipoamide dehydrogenase enzyme are the cause of dihydrolipoamide dehydrogenase deficiency, an autosomal recessive disease characterized by lactic acidosis, which results from the accumulation of lactic acid in the body. Additionally, certain amino acids (valine, isoleucine, and leucine) and their metabolites build up in cells leading to neural damage. The latter manifests itself though seizures and developmental delay.