The genetics of sporadic ruptured and unruptured intracranial aneurysms: a genetic meta-analysis of 8 genes and 13 polymorphisms in approximately 20,000 individuals

OBJECT: Intracranial aneurysms (IAs) are thought to have a multifactorial origin. The authors undertook a comprehensive meta-analysis on all genes investigated using a case-control model in ruptured (subarachnoid hemorrhage) and unruptured aneurysms. METHODS: Electronic databases were searched until and including July 2008 for any candidate gene studied in IA or subarachnoid hemorrhage using a case-control model. The ORs and 95% CIs were determined for each gene-disease association using fixed and random effect models. RESULTS: Thirty studies of 8 genes and 13 polymorphisms were analyzed among 19,961 individuals (6622 cases and 13,339 controls). Two genes and 3 polymorphisms were associated with IA. The eNOS gene T786C polymorphism (OR 1.24, 95% CI 1.0-1.54; p = 0.05) and IL-6 gene G572C polymorphism (OR 7.08, 95% CI 2.85-17.57; p < 0.0001) both showed a significant association with ruptured/unruptured IA. The IL-6/G174C polymorphism exerted a significant protective effect against IA (OR 0.49, 95% CI 0.25-0.95; p = 0.04). The other candidate genes investigated (ACE, endoglin, APOE, elastin, MMP-3, and SERPINA3) showed no significant associations. CONCLUSIONS: There is a likely genetic basis to sporadic IAs. However, the evidence base is small when compared against other complex disorders.