Hotspot mutations in IDH1, of which IDH1R132H is the most prevalent in glioma and chondrosarcoma, lead to heterodimeric enzymes (IDH1WT/MUT), loss of wild-type IDH1 enzyme function and a neomorphic IDH1 activity that converts αKG into the oncometabolite D-2-hydroxyglutarate (D-2HG) [10]. The gene discussed is IDH1; the disease is glioma.