The treatment for patients with malignant brain tumors is disappointing. The disease is incurable and virtually all patients die from their disease. Despite the devastating nature of this illness which affects all age groups, its cause remains unexplained. Family identification with careful clinical and molecular study have led to the discovery of the genes that cause a number of other devastating diseases like retinoblastoma, cystic fibrosis, and Huntington's chorea. The investigators propose to study the genetic changes in patients with familial glioma as a first step in identifying the gene(s) that cause these tumors.