IDH1 and glioblastoma: For example, mutations in the isocitrate dehydrogenase 1 (IDH1) gene lead to intracellular accumulation of 2‐hydroxyglutarate (2‐HG) and induce glioblastoma (GBM).[3] In addition to genetic mutations, abnormal epigenetic regulation is also an important factor in CNS disease development.