DLD is an L protein of the mitochondrial glycine cleavage system which is also a component of the pyruvate dehydrogenase complex, the alpha-ketoglutarate dehydrogenase complex, and the branched-chain alpha-keto acide dehydrogenase complex. DLD mutations were found in patients with E3-deficient maple syrup urine disease and lipoamide dehydrogenase deficiency.