It was shown that mutant IDH not only has reduced capacity to convert isocitrate to α-ketoglutarate but also acquires a novel reductive activity utilizing α-ketoglutarate to produce 2 hydroxyglutarate (2HG) (Dang et al, 2009), which is tumorigenic in glioma and AML. The gene discussed is IDH2; the disease is central nervous system cancer.