Consequently, pushing the boundaries of surgical resection when there is a possible increased risk of disability might be in the patient’s best interest if they have an IDH-mutant astrocytoma but would not be in their interest if they have an oligodendroglioma: intraoperative information of the glioma genetic subtyping is therefore essential. The gene discussed is IDH1; the disease is astrocytoma (excluding glioblastoma).