In the context of acute myeloid leukemia (AML) and glioma, oncogenic mutations in isocitrate dehydrogenases IDH1 and IDH2 result in the conversion of α-ketoglutarate to 2-hydroxyglutarate (2HG), a substance that inhibits Jumonji-C domain histone demethylases (JHDMs) and TET dioxygenase, involved in DNA demethylation. The gene discussed is IDH2; the disease is acute myeloid leukemia.