Three common single-nucleotide variants in the promoter region of thymic stromal lymphopoietin cytokine are not associated with asthma prevalence in a Saudi Arabian population

Abstract

Background: Thymic stromal lymphopoietin (TSLP) is recognized for its key role in promoting asthma, hence drawing considerable clinical interest as a potential therapeutic target. Population-based studies found association between single nucleotide polymorphisms (SNPs) located in the TSLP promoter region, and asthma; however, discrepancies have been also reported. Aims and Objectives: To determine whether rs1837253, rs2289276, and rs3806933 SNPs of TSLP gene are associated with asthma predisposition in a Saudi population. Materials and Methods: A total of, 272 asthmatic patients and 398 normal controls, all of Saudi citizenship, were recruited. The TSLP target DNA sequences were polymerase chain reaction (PCR) amplified using specific primers and allelic determination was performed by Sanger sequencing and capillary electrophoresis. Results: The relative frequencies for the minor allele, “T,” in all three SNPs, were smaller in asthmatics although not significant. When testing for genotypes, the homozygous T/T of all three SNPs was less frequent in asthmatic patients, but not to statistically significant levels. Both the recessive and dominant genetic models were tested. Homozygous T/T individuals for each SNP had lower odds of being asthmatics, thus suggesting a “protective” effect, although none of the SNPs in either model reached a statistical significance. Conclusion: Three SNPs in TSLP's promoter gene were not significantly associated with asthma in the Saudi population.

Keywords

• allergy
• association analysis
• atopic asthma
• genotyping
• risk
• rs1837253
• rs2289276
• rs3806933
• saudi arabia
• thymic stromal lymphopoietin