In line with prior expectations, there were significant differences in age between all diagnoses (ANOVA P < 0.0001, post hoc Tukey honest significance tests all P < 0.001), yielding an oldest to youngest order from (i) glioblastoma, IDH-wildtype; (ii) oligodendroglioma, IDH-mutant, and 1p/19q-codeleted; (iii) astrocytoma, IDH-mutant; to (iv) other glioma. This evidence concerns the gene IDH1 and glioma.