Patients with IDH1 mutations were younger for the whole series (median age 40.6 years for IDH1 mutated patients versus 55.9 years; P < 0.0001) and also for grades III and IV separately (median age at diagnosis 44.4 and 47.8 years for grades III and IV IDH mutated tumors, versus 51.5 and 59.0 years for grades III and IV nonmutated gliomas; P = 0.0012 and P < 0.0001, resp). The gene discussed is IDH2; the disease is central nervous system cancer.