Other than these two entities, the WHO classification of CNS tumors 2021 recognizes the following types of IDH‐mutant gliomas: diffuse astrocytoma (WHO grade II), anaplastic astrocytoma (WHO grade III), oligodendroglioma 1p/19q‐codeleted (WHO grade II), and anaplastic oligodendroglioma 1p/19q‐codeleted (WHO grade III) [9]. The gene discussed is IDH1; the disease is oligodendroglioma.