As a result of these advances, the 2021 WHO Classification gathers as adult Glioma Grade 4 (GG4) both the Astrocytomas IDH-mutant Grade 4 and the astrocytoma IDH wild-type, which in turn currently defines the Glioblastoma (GBM) class [7]. The gene discussed is IDH1; the disease is astrocytoma (excluding glioblastoma).