Isocitrate dehydrogenase (IDH) catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. The isocitrate and isopropylmalate dehydrogenases family has three members, IDH1, IDH2 and IDH3. IDH2 plays a role in intermediary metabolism and energy production. Defects in IDH2 are the cause of D-2-hydroxyglutaric aciduria type 2 (D2HGA2). Somatic mosaic mutations of this protein have also been found associated to Ollier disease and Maffucci syndrome, and R172S IDH2 mutations do exist in diffusely infiltrative gliomas.