Taste Thresholds of Phenylthiocarbamide and 6-n-Propylthiouracil and their Correlation with TAS2R38 Genotype / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Phenylthiocarbamide (PTC) and its chemically related compound,6-n-propylthiouracil (PROP), both produce a taste that is extremely bitter to some subjects (tasters) but tasteless or only slightly bitter to others (non-tasters). Earlier studies had used PTC, but most investigators have switched to PROP because of its several advantages. Recently, three single nucleotide polymorphisms in the TAS2R38 gene were identified and several studies have demonstrated a strong association between these genes with taster status. The aim of this study was to investigate the relationship between taste thresholds of PTC and PROP and their correlation with the TAS2R38 genotype. SUBJECTS AND METHOD: Seventy-five healthy normal volunteers were included. Taster status was determined using successive solutions of PTC and PROP, which comprised a total of 15 grades. All participants were genotyped for polymorphism of the TAS2R38 gene that affects taste sensitivity to PTC and PROP. RESULTS: PTC taste thresholds showed 96% correlation with the taste thresholds for PROP. Non-tasters defined by the PTC threshold test were the exactly the same with those identified as AVI (alanine, valine, isoleucine) homozygous, but taster status determined by the PROP threshold test showed 96% correlation with the genotypes. CONCLUSION: The PTC threshold test was more reliable for determining taste blindness than the PROP threshold test.