Object. The COL1A2 gene at 7q22.1 has been shown to be associated with familial intracranial aneurysms (IAs) the correlation between the presence of the in the Japanese population. In the present study. the authors investigated rs42524 polymorphism in COL1A2 and the Occurrence of sporadic IAs in Chinese patients. Methods. The polymorphism rs42524 of the COL1A2 gene was identified by polymerase chain reaction-based restriction analysis in genomic DNA from 226 patients with sporadic IAs (mean age 51.49 +/- 11.47 years) and 326 control participants (mean age 52.33 +/- 10.50 years). Neurological assessments were performed using the HUM and Hess grading system. and differences in allelic and genotypic frequencies between the patient and control groups were evaluated with the chi-square test. Results. There was a significant difference in either the genotype distribution (chi(2) = 11.997 p = 0.002) or allelic frequencies (chi(2) = 11.96, p = 0.001. odds ratio 2.579, 95% confidence interval 1.486-4.476) between patients with IAs and patients in the control group. Conclusions. The rs42524 polymorphism of COL1A-2 could be a genetic risk factor for sporadic IAs among individuals of Chinese Han ethnicity. This study is the first to confirm the association between COL1A2 and IAs. (DOI: 10.3171.JNS.2008.109.12.1060)