Glioblastoma (GBM), as defined by the 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors, is an isocitrate dehydrogenase (IDH) wildtype and histone 3 (H3) wildtype tumor with predominantly astrocytic differentiation and at least one of the following: microvascular proliferation, necrosis, TERT promoter mutation, EGFR gene amplification, and +7/10 chromosome copy-number changes [1]. The gene discussed is IDH3A; the disease is glioblastoma.