Within the category of “gliomas, glioneuronal and neuronal tumors”, six large groups of diffuse gliomas are defined: (1) Adults diffuse gliomas, including three types (Grade 2, 3 or 4 Isocitrate Dehydrogenase (IDH)-mutated diffuse astrocytomas, grade 2 or 3 IDH-mutated diffuse astrocytomas, and grade 4 IDH-mutated astrocytoma or Glioblastomas), (2) Pediatric-type diffuse low-grade gliomas, (3) Pediatric-type diffuse high-grade gliomas, (4) Circumscribed astrocytic gliomas, (5) Glioneuronal and neuronal tumors, and (6) Ependymal tumors [4]. Here, IDH3A is linked to diffuse astrocytoma.