This study aims to investigate overall survival and clinical characteristics of <i>IDH</i>-mutated glioma with a hemizygous deletion of <i>CDKN2A/B</i>.<h4>Method</h4>A total of 215 consecutive patients with <i>IDH</i>-mutated glioma, WHO grade 2 and 3, who underwent primary surgery between 2007 and 2023 in a defined catchment area were included. This evidence concerns the gene CDKN2A and glioma.