Genetics of ischemic and hemorrhagic stroke in Chinese population

Stroke is a major cause of adult death and disability worldwide. Epidemiological and animal studies have provided strong evidence that the pathogenesis of stroke is multi-factorial and induced by a combination of environmental and genetic risk factors, but the identification of individual causative variants remains little known. Genetic influences are likely to be polygenic with small effect sizes, and stroke itself consists of a number of different subtypes which may each have different genetic profiles. In addition, various ethnic populations may have different stroke risk, such as Asian race. The reasons for high risk of stroke among the Chinese, especially hemorrhagic stroke, remain unknown. Most human studies have taken a candidate gene approach using case-control methodology. To be reliably detected, small relative risks require large sample sizes, probably 1000 patients or more. Genome-wide association (GWA) study is an unbiased and comprehensive approach to identify common risk alleles for complex diseases. Recently, a multistage GWA study has identified three loci on chromosomes 2q, 8q and 9p to be associated with intracranial aneurysm in European and Japanese populations. Another GWA finding is the identification of risk variants for cardioembolic stroke on chromosome 4q25 in European populations. In this review, we mainly focus on the results from case-control association studies on genetic factors that play a role in the risk of ischemic and hemorrhagic stroke in Chinese population. The combined effects of multiple susceptibility genes for stroke risk are also summarized.