Association between an indel polymorphism in the 3'UTR of COL1A2 and the risk of sudden cardiac death in Chinese populations.

Sudden cardiac death (SCD) describes the unexpected natural death from a cardiac cause within a short time period. Compelling evidence suggests the involvement of host genetic factors in SCD etiology. Identification of genetic variations predisposed to SCD enables genetic testing that may contribute to SCD diagnosis and risk stratification. Previous studies have suggested that dysregulation of pro-alpha2 chain of type I collagen, encoded by collagen type I alpha 2 chain (COL1A2) gene, was involved in cardiac disorders such as myocardial infarction, hypertrophic cardiomyopathy and atherosclerosis. By using a candidate-gene-based approach, we evaluated the association of a 7-base pair (7-bp) indel polymorphism (rs3917) in the 3'UTR of COL1A2 with the risk of SCD in a Chinese population (79SCD cases and 328 controls). Logistic regression analysis showed that the deletion allele of rs3917 significantly increased the risk of SCD [odds ratio (OR)=1.82; 95% confidence interval (CI)=1.08-3.06; P=0.0159]. Further genotype-phenotype association analysis revealed that the deletion allele was markedly correlated with lower expression of COL1A2 in human myocardium tissues. The luciferase activity analysis in an in vitro reporter gene system suggested that rs3917 could regulate COL1A2 expression through interrupting the binding of miR-296-3p with COL1A2 in an allele-dependent manner, which in turn confer SCD risk. Our data provided initial evidence that rs3917 was highly relevant to SCD susceptibility, and this indel may become a potential marker for molecular diagnosis and genetic counseling of SCD. The replication of our studies and further functional studies are needed to validate our findings.