Familial intracranial aneurysms: recurrence risk and accidental aggregation study

Area of Science:

• Neuroscience
• Genetics
• Epidemiology

Background:

• The Saguenay-Lac-Saint-Jean (SLSJ) region in Quebec, Canada, exhibits a high familial aggregation of ruptured intracranial aneurysm (RIA).
• Population-based data revealed 28.7% of RIA cases had familial aggregation, significantly higher than global reports.

Purpose of the Study:

• To assess genetic predisposition to RIA in the SLSJ population.
• Compare familial and non-familial RIA cases.
• Estimate the recurrence risk ratio for siblings of RIA patients.

Main Methods:

• Utilized a population-based register for genealogical reconstruction of 502 individuals with RIA.
• Compared clinical characteristics (age at rupture, aneurysm count, location) between familial and non-familial groups.
• Calculated the recurrence risk ratio for siblings using population prevalence.

Main Results:

• No significant differences in age at rupture, aneurysm count, or location between familial and non-familial RIA cases.
• 20 out of 3449 siblings (0.58%) had experienced a RIA.
• The sibling recurrence risk ratio for RIA was estimated at 1.6 (95% CI 1.0-2.4).

Conclusions:

• Siblings of RIA patients in the SLSJ region face a higher risk than the general population.
• The high familial occurrence is largely attributed to large kinship sizes in the SLSJ population.
• Suspect underlying genetic predisposition for RIA only when three or more first- to third-degree relatives are affected.