TERT promoter mutations seen in > 95% patients with IDH mutant oligodendroglioma and uncommonly in IDH mutant astrocytoma (Koelsche et al., 2013; Suzuki et al., 2015; Arita et al., 2013; Labussiere et al., 2014); TERT wild-type tumors seen in teenage patient (Lee et al., 2018). The gene discussed is IDH1; the disease is oligodendroglioma.