HMGCL and metabolic disease: Fatty acid oxidation disorders are major metabolic disorders that are classified into several types, including deficiency of the following enzymes: very long-chain acyl-CoA dehydrogenase, 3-hydroxy-3-methylglutaryl-CoA lyase, and carnitine palmitoyl transferase II; caused by mutations of these genetic variants ACADVL, HMGCL, and CPT2, respectively [39].