IDH2 is frequently mutated in glioma, acute myeloid leukemia and myelodysplastic syndromes. Mutations generally involve point mutations at residues R140 and R172 of the protein. Mutations in IDH1 and IDH2 result in a detrimental “gain of function”: instead of converting isocitrate to α-ketoglutarate, mutated IDH1 or IDH2 converts isocitrate to 2-hydroxyglutarate. 2-hydroxyglutarate inhibits other proteins involved in epigenetic regulation.