Patients with an IDH mutation, in either oligodendroglioma or astrocytoma, were younger (mean ages 46.6 and 45.7 years, respectively) than patients with IDH Wt astrocytoma or GBM (mean age 65.1 and 63.6 years, respectively) (P ≤ 0.05). Here, IDH1 is linked to oligodendroglioma.