OBJECTIVETo investigate the association of serotonin transporter gene linked polymorphic region (5-HTTLPR) insertion/deletion polymorphism with early onset myocardial infarction(MI) and platelet membrane glycoprotein I b(GP I b) in Northern Han population of China.

METHODSA total of 150 patients with early onset MI and 150 age- and sex-matched controls with negative coronary arteriography were genotyped for the 5-HTTLPR polymorphism by using a polymerase chain reaction-based technique. The percentage of positive platelet membrane GP I b and the average fluorescence intensity were quantified by flow cytometry.

RESULTSThe genotype frequencies of LL, LS and SS in the 5-HTTLPR were 32%, 47% and 21% in the MI patients, 17%, 43% and 39% in the controls respectively(P<0.01). The L allele frequency in the MI patients was significantly higher than that of the control group (56% vs 39%, P<0.01). The percentage of positive platelet membrane GP I b and the fluorescence intensity in subjects with LL homozygote were markedly lower than that of LS and SS genotypes in the MI and control groups (all P<0.01). Multivariate logistic regression analysis showed that the 5-HTTLPR LL genotype was independently related to the occurrence of early onset MI(OR was 1.961, P was 0.037).

CONCLUSIONThe LL genotype of the 5-HTTLPR might be associated with the susceptibility to developing early MI in Northern Han population of China. The platelet activation is increased in individuals of LL genotype.