A small proportion of glioma patients have a family history of brain tumours. A subset of these cases carries pathogenic germline alterations in tumour suppressor genes as part of a tumour suppressor syndrome. These rare syndromes increase the risk of developing glioma in relatives of patients. Therefore most of the genetic risk remains unaccounted for. Sequencing studies of a large cohort of cancer patients, including glioma, identified several pathogenic germline variants in known cancer predisposition genes. Pairing these findings with other datasets enabled the authors to show copy number alterations and changes in the expression of the genes carrying these variants. Studying the co-segregation of the disease and rare mutations in families could also identify causal variants.