Objective: To assess the association of SLC6A4 gene c.*670T>G polymorphism with the risk for asthma and peripheral blood cytological characteristics among ethnic Zhuang Chinese from Guangxi, China.
Methods: From May 2017 to March 2020, 258 patients diagnosed with asthma and 244 healthy controls were recruited from the Affiliated Hospital of Youjiang Minzhu Medical College and the People's Hospital of Hechi. Genotypes of the c.*670T>G polymorphism were determined by Sanger sequencing. Flow cytometry was used in combination with an electrical impedance method for the counting and classification of peripheral blood cells.
Results: Compared with the T allele, the G allele of the c.*670T>G polymorphism was associated with the risk for asthma in the population (OR = 1.54, 95%CI = 1.15-2.06; P = 0.004). Compared with the GT and TT genotypes, homozygous GG genotype also comprised a risk factor (OR = 1.66, 95%CI = 1.16-2.38; P = 0.005). Stratification of the risk factors showed that the homozygous GG genotype has increased the risk of asthma in males and urban residents (P < 0.01). The erythrocyte, hemoglobin and platelet counts of the asthma group were significantly higher than the control group (P < 0.001). The GG, GT and TT genotypes have respectively accounted for 82.35%, 17.65% and 0% of the samples with platelets exceeding the normal value. The overall platelet level of GG genotype was higher than GT+TT genotype (P < 0.05). The significant association was verified by the false positive report probability, and at a prior probability level of 0.1, G vs. T false positive probability was 0.071, and GG vs. GT+TT false positive probability was 0.153.
Conclusion: The GG genotype of the c.*670T>G polymorphism is associated with the risk for asthma among ethnic Zhuang Chinese from northwest Guangxi. Above finding has also enriched the genotypic data and peripheral blood phenotype for this polymorphism.