IDH1 and glioma: The most recent guidelines for the classification of gliomas recommend that LGG should be categorized into three major groups81: (1) IDH-mutated 1p/19q codeleted group; (2) IDH-mutated 1p/19q non-codeleted group (most of them have mutations in TP53 and ATRX); (3) IDH-wildtype 1p/19q non-codeleted group.