The 2016 World Health Organization (WHO) classification of gliomas, by integrating histopathological features with molecular alterations, classifies astrocytic tumours based on the mutational status of IDH1/2 and H3K27M genes, while oligodendrogliomas are defined by the co-occurrence of IDH1/IDH2 mutation and codeletion of whole chromosomal arms 1p and 19q [1]. The gene discussed is IDH2; the disease is oligodendroglioma.