Association Between Genetically Determined Serum Corin and the Risk of Stroke in Chinese Adults: A Mendelian Randomization Study.

BACKGROUND: Serum corin has been associated with stroke in observational studies, but the underlying causality is uncertain. This study examined the causal association between corin and stroke through Mendelian randomization study. METHODS AND RESULTS: In the Gusu cohort, serum corin was assayed at baseline, and stroke incidents were prospectively obtained during 10 years of follow-up. Single-nucleotide polymorphisms (SNPs) in CORIN were genotyped by MassArray for 2310 participants (mean age, 53 years; 39% men). Seventeen SNPs passed the Hardy-Weinberg test and were considered the potential instruments. Only 1 SNP (rs2271037) determined variability of serum corin was significantly associated with stroke even after adjusting for conventional risk factors (hazard ratio [HR], 1.36 [95% CI, 1.00-1.85]). The weighted genetic risk score generated from the SNP-corin associations was significantly associated with stroke (HR, 2.01 [95% CI, 1.15-3.51]). Using this genetic risk score as the instrument, 1-sample Mendelian randomization analysis found a significant HR of stroke per-SD higher log(2)-transformed corin (HR, 1.37 [95% CI, 1.07-1.76]). The inverse variance-weighted analysis based on the SNP-corin and SNP-stroke associations found that the HR of stroke pre-SD higher log(2)-transformed corin was 5.92 (95% CI, 2.23-15.72). The effect estimates stayed consistent regardless of an individual SNP being removed from the instruments. An almost identical effect estimate was also confirmed by multiple other 2-sample Mendelian randomization methods. CONCLUSIONS: Genetically determined variations of serum corin concentration were significantly associated with the risk of stroke in Chinese adults. Elevated serum corin may be a risk factor for stroke.