With nearly 96% IDH mutant gliomas harboring an IDH1 mutation (Hartmann et al., 2009), the predominant alteration is IDH1:c.395G > A p. R132H (83–91%) (Balss et al., 2008), followed by IDH1:c.394C > T p. R132C (3.6–4.6%), p. R132G (0.8–2.5%), p. R132S (0.6–3.8%) and p. R132L (0.5–4.4%) of all IDH1 mutations (Balss et al., 2008). The gene discussed is IDH2; the disease is central nervous system cancer.