MATERIAL and METHODS: We identified six families in which at least two first-degree relative members had an IA in our database. In five families, we screened 95 first-degree relatives of affected members.

RESULTS: As a result of our screening, we identified 9 unruptured aneurysms in 95 individuals for a total yield of 9.4%. There was a prominent female preponderance in affected family members and nearly half of the aneurysms were on the middle cerebral artery (MCA). Most of the affected relatives were siblings.

CONCLUSION: Our results support a general recommendation to screen first-degree relatives of IA patients from families with two or more cases of IA. Familial aggregation of IA's is not only useful in identifying asymptomatic individuals harboring unruptured aneurysms but also implicates a genetic contribution to the pathogenesis of this disease in different patient populations. Keywords : Screening, Family, Intracranial aneurysm