Familial risks in nervous system tumors.

We used the nationwide Swedish Family-Cancer Database to analyze the risk for nervous system tumors in offspring through parental and sibling probands. Among 0-68-year-old offspring, close to 11000 patients with a nervous system tumor were identified in years 1961 to 2000, among whom 199 had a parent diagnosed with a nervous system tumor. Brain tumors constituted 86% of all tumors, and astrocytoma was the main histological type, representing half of all cases. Standardized incidence ratios (SIRs) for familial risk were only increased for brain tumors of meningioma, astrocytoma, and hemangioblastoma histology. When parents were diagnosed with tumors of the same histology, the SIRs for offspring were 3.06, 2.19, and 165 for meningioma, astrocytoma, and hemangioblastoma, respectively. Among siblings, the SIRs were 4.41, 3.20, and 61. Age-specific analysis of familial astrocytoma revealed three distinct components, one < 10 years, the second approximately age 30 years, and the third at age >60 years. The kappa test was used to assess the likelihood of an identical histology in two family members. The occurrence of hemangioblastoma was completely determined among the siblings, and the kappa value was 1.00. Meningiomas were also moderately ordered among the siblings, but astrocytomas were less determined. Many syndromes are known in which nervous system tumors are manifestations, including hemangioblastoma, recognized as part of von Hippel-Lindau disease. Yet, it is likely that many brain astrocytoma, meningioma, and mixed families represent yet unknown heritable conditions.