FAMILIAL INTRACRANIAL ANEURYSMS

Background We set out to determine the prevalence of incidental intrac ranial aneurysms in first-degree relatives aged 30 years or more of pe ople with intracranial aneurysms, and to see if polycystic kidney dise ase contributes to the aggregation of familial intracranial aneurysms. Methods 91 families with two or more affected members had previously been identified from a 14 year series of 1150 intracranial aneurysm pa tients treated at the University Hospital of Kuopio, Finland. Magnetic resonance angiography was used as a preliminary screening method, fol lowed by conventional four-vessel angiography to verify suspected aneu rysms. Participants were also screened for polycystic kidneys by ultra sonography. Findings Incidental aneurysms were detected in 40 individu als: 38 of 438 individuals from 85 families without polycystic kidney disease or other diagnosed heritable disorders, and two of 22 individu als from six families known to have polycystic kidney disease. The cru de and age-adjusted prevalence of incidental intracranial aneurysms am ong screened first-degree relatives was 8.7 (SE 1.3)% (95% CI 6.2-11.7 ) and 9.1(1.4)% (6.2-11.7), respectively, for the familial group and t he crude prevalence for the polycystic kidney group was 9.1 (6.1)% (1. 1-29.2). Interpretation Our results demonstrate a high prevalence of i ncidental intracranial aneurysms among first-degree relatives aged 30 years or older of patients with the condition and indicate that the ri sk of having an aneurysm is about four times higher for a close relati ve than for someone from the general population. Also, polycystic kidn ey disease families are a small fraction of the familial intracranial aneurysm families.