Role of the TAS2R38 Bitter Taste Receptor Gene Single Nucleotide Polymorphism in Patients with Taste Disorders

Background and Objectives Several studies have shown that three single nucleotide polymorphisms (SNPs) in the TAS2R38 gene demonstrate a strong association with the ability to sense the bitter taste of phenylthiocarbamide (PTC) in. We have previously reported about TAS2R38 genotypes in normal volunteers. The aim of this study was to investigate the role TAS2R38 gene plays in taste disorder by examining SNPs in the TAS2R38 gene in taste disorder patients. Subjects and Method Ninety-four patients with taste dysfunction from multiple etiologies were enrolled. The genotypes were defined by identifying SNPs on the TAS2R38 gene. The proportion of different TAS2R38 genotypes in the group was compared with that in the normal volunteers of our previous study. The whole mouth taste threshold tests were performed and the thresholds were compared among the three different genotypic groups. Results The proportion of each diplotype in taste disorder patients were as follows: PAV/ PAV 36.2% (34/94), PAV/AVI 34.0% (32/94), and AVI/AVI 29.8% (28/94). The proportion of AVI/AVI type was higher in the group than in the normal volunteers (p=0.031). The detection and recognition thresholds of all four basic tastes were increased in the order of PAV/PAV, PAV/AVI, and AVI/AVI genotypes. Conclusion The proportion of AVI/AVI homozygous was significantly higher in taste disorder patients than in the normal volunteers. Our findings suggest that the genotypes of TAS2R38 may represent one of the risk factors responsible for the development of taste disorders.