Association between polymorphisms in bitter taste receptors genes and clinical features in Korean asthmatics

Background: Bitter taste receptors (TAS2R) in human airway smooth muscle have been recently shown to have an important role in bronchodilation, together with β2-adrenergic receptors.

Object: To evaluate the association between genetic variations in TAS2R and clinical features, including bronchodilator response and asthma control.

Method: We analysed the association between single nucleotide polymorphisms (SNPs) of TAS2R10 and TAS2R14 and variables including demographic data, atopy, duration of disease, asthma control status, including variables such as asthma control test (ACT) score, percent predicted value of FEV₁, forced vital capacity (FVC), and FEV₁/FVC ratio, and bronchodilator response (BDR), in 721 asthma patients in Korea.

Result: Three novel SNPs of M207I, H203Q, and -79G/A in TAS2R10 and three known SNPs of -815C/T, -1267A/G, and -1897C/T in TAS2R14 were analysed. Increased BDR was significantly associated with SNP of -815T>C [OR (95% confidence interval (CI)) = 1.88 (1.01 – 3.49), p=0.04 ], -1267 A>G [OR (95% CI) = 2.07 (1.03 – 4.15), p=0.04] and -1897C>T [OR (95% CI) = 3.05 (1.01 – 9.23), p=0.04, and OR=1.91 (1.08−3.36), p=0.02] of the TAS2R14 gene. There was a significant association between -815 T>C and low mean ACT score [OR (95% CI) = 5.84 (1.94 – 17.61), p=0.001]. In haplotype analysis, TGT, CAT, and TGT, or TG and CA haplotypes on TAS2R14 were significantly associated with increased BDR; CAT and CA haplotypes were significantly associated with low ACT score.

Conclusion: Genetic variations in TAS2R may be valuable genetic markers to predict therapeutic response and outcomes in asthma, although we had not sufficiently clarified the relationship between genetic polymorphism in TAS2R genes and the response to ß2-adrenoreceptor agonists. Further research in an independent cohort is needed.