In addition, 2016 WHO classification of the central nervous system (CNS) tumors classified gliomas into astrocytic tumors, oligodendrogliomas, and not otherwise specified (NOS) not only based on histology but also molecular features, including isocitrate dehydrogenase (IDH) mutational and 1p/19q codeletion status (Wen and Huse, 2016; Wen and Huse, 2017). The gene discussed is IDH3A; the disease is glioma.