Familial aggregation of intracranial aneurysms in an Inuit patient population in Kalaallit Nunaat (Greenland)

OBJECTIVE: The incidence of subarachnoid hemorrhage (SAH) and intracranial aneurysm (IA) has been reported to be higher in Greenlandic Inuits than in Caucasian Danes, but the rate of familial aggregation in Inuits is unknown. METHODS: This study retrospectively compared the rate of familial aggregation of SAH and IA (at least one first- or second-degree relative with presumed SAH and/or IA) in 120 Inuit patients from Greenland admitted to the Copenhagen University Hospital in Copenhagen, Denmark, from 1978 to 1998 with a diagnosis of ruptured IA with that in 1037 Caucasian Danes admitted from 1978 to 1983. RESULTS: Inuit patients had a much higher rate of familial history of SAH (23.1%) and of IA (9.6%) than Danish patients (4.3 and 1.6%, respectively). In both populations, familial SAH was associated with lower age at the time of aneurysm rupture. Danish patients with familial SAH showed a higher rate of middle cerebral artery aneurysms (40 versus 26% in sporadic SAH). In Inuit patients with familial and nonfamilial SAH, 42 and 38% of the aneurysms originated from the middle cerebral artery. The overall rate of multiple aneurysms was highest among Inuits, and in both populations, it was increased in the presence of a positive family history. CONCLUSION: The rate of a positive family history of presumed SAH and IA is high among Inuits who present with SAH compared with Caucasian Danes who present with SAH. This finding, coupled with a higher rate of multiple aneurysms and younger age at presentation, suggests a potential genetic influence among Inuit families.