D2HGDH (D-2-Hydroxyglutarate Dehydrogenase) is a mitochondrial enzyme involved in the metabolism of D-2-hydroxyglutarate, a cellular byproduct. It helps prevent the harmful buildup of this compound. Dysfunction of D2HGDH is linked to D-2-hydroxyglutaric aciduria, a condition associated with symptoms such as developmental delays, epilepsy, and heart problems.