IDH3A and glioblastoma: In addition, according to the upcoming 2021 WHO Classification of Tumors of the Central Nervous System (CNS) [9], previously called glioblastoma, isocitrate dehydrogenase (IDH)-mutant is now designated as astrocytoma, IDH-mutant, WHO grade 4 and glioblastoma should be diagnosed in the setting of IDH wildtype.