Thrombomodulin Ala455Val polymorphism and risk of coronary heart disease

Background-Thrombomodulin (TM) is expressed on the endothelial surface and plays an important role in vasoprotection. A common polymorphism of TM at a mino acid position 455 with an alanine (A) to valine (V) transition was pre viously reported to be associated cross-sectionally with acute myocardial i nfarction. Whether this single nucleotide polymorphism predicts risk of dev eloping coronary heart disease (CHD) is unclear. Methods and Results-Within a large cohort study, we identified 467 incident CHD cases during an average of 5 years of follow-up. We determined TM-455 genotypes on 376 CHD cases (23% black, 77% white) and a reference sample of 461. The AA genotype was significantly more prevalent in noncases than in cases (P=0.016), The prevalences of the AA genotype in noncase blacks and w hites were 93% and 67%, respectively. The AA genotype frequency was signifi cantly reduced in black cases versus noncases (P=0.018). It was also lower in white cases than in noncases, but the difference was not statistically s ignificant (P=0.066), Weighted proportional hazards regression analysis aft er adjustment for age, sex, and other CHD risk factors showed that having t he V allele increased risk of CHD by 6.1-fold (risk ratio 6.1, 95% CI 1.7 t o 22.9) in blacks but did not significantly increase the risk in whites. Conclusions-The TM A455V polymorphism predicts risk of developing CHD in bl acks.