D-2-hydroxyglutaric aciduria is a rare autosomal recessive organic aciduria with variable clinical expression. The biochemical defect is still unknown. There are two disorders that result in the build up of 2-hydroxyglutaric acid, these are D2-hydroxyglutaric aciduria and L2-hydroxyglutaric aciduria. They are separate unrelated diseases. In D2 hydroxyglutaric aciduria the actual enzyme that is deficient or absent is not currently known.