The last update (2016) of the WHO classification of CNS tumors recognizes established molecular variants of HGG including IDH-wildtype and -mutant GBM, as well as H3.3/H3.1 K27-mutant diffuse midline glioma, which were formerly known as diffuse intrinsic pontine glioma (DIPG). The gene discussed is IDH1; the disease is diffuse intrinsic pontine glioma.