Isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2) are commonly mutated in most low-grade gliomas and secondary glioblastoma multiforme26,27, and IDH mutation status is a feature of glioma subclassifications in the 2016 World Health Organization classification28. The gene discussed is IDH1; the disease is glioma.