Genetic variants of SLC6A4 and risk of coronary artery disease: insights from North Indian population.

BACKGROUND

The activity of SLC6A4 is influenced by its polymorphisms, including the length variation in serotonin transporter linked promoter region (5-HTTLPR), a single nucleotide polymorphism (rs25531), and variable number of tandem repeats in serotonin transporter intronic enhancer (STin2). These polymorphisms have been implicated in the development of vascular diseases. Our research aimed to determine whether the bi-allelic 5-HTTLPR, tri-allelic 5-HTTLPR (rs25531), and STin2 polymorphisms of SLC6A4 were associated with an increased risk of coronary artery disease (CAD) in the North Indian population of Jammu region in Jammu and Kashmir state of India.

METHODS

In this study, we performed a large cohort case-control study. Here, we recruited 400 patients clinically diagnosed with CAD, and 400 unrelated healthy individuals with similar sex and age range. We performed Polymerase Chain Reaction (PCR) for genotyping the 5-HTTLPR and STin2 polymorphisms. In addition, PCR- Restriction Fragment Length polymorphism (RFLP) was used to perform restriction fragment length polymorphism for the rs25531. Finally, we performed statistical analysis with the yield data.

RESULTS

The L-allele of 5-HTTLPR was significantly associated with CAD susceptibility, with an odd ratio (OR) of 1.39 and a p-value of 0.01. However, no significant association was identified for the tri-allelic 5-HTTLPR (rs25531) and STin2 polymorphism with the susceptibility of CAD. The haplotype combinations associated with CAD outcomes include L-12 and LA-10.

CONCLUSIONS

Although, majority of the previous studies have evaluated the association of 5-HTTLPR biallelic polymorphism with CAD, our findings suggested that the tri-allelic 5-HTTLPR (rs25531) is a more reliable candidate than the bi-allelic 5-HTTLPR, as studying the bi-allelic version alone may generate association bias. Based on the results of this study, the rs25531 and STin2 polymorphisms indicated that the SLC6A4 gene does not contribute to the development of CAD in the population of the of Jammu region in Jammu and Kashmir state of India.