Relationship between PTC Genotype and Taste Phenotype in Normal Volunteers

Ye, Mi Kyung; Shin, Tae Hyun

Abstract

BACKGROUND AND OBJECTIVES: The ability to taste the bitter compounds phenylthiocarbamide is a classic inherited trait in humans. This trait has also been shown to correlate with a number of dietary preferences and thus may have important implications for human health. Recently, the PTC gene that underlies the phenotype was identified. Three single nucleotide polymorphisms in the PTC gene that result in three aminoacid substitutions (A49P, V262A, I296V) demonstrated a strong association with taster status in several studies. The aim of this study was to investigate the relationship between PTC genotype and taster status in normal volunteers.
SUBJECTS AND METHOD
Seventy-three healthy normal volunteers were included. Phenylthiocarbamide detection threshold test was performed with successive solutions, which was comprised of a total of 15 grades. PTC gene haplotypes were defined by havingsingle nucleotide polymorphisms at the base pairs, 145,785 and 886, on the PTC gene.
RESULTS
Taste sensitivity to phenylthiocarbamide had a bimodal distribution, which givesrise to the practice of dichotomizing subjects into 'tasters' and 'non-tasters'. The percentages of taster and non-taster were 80.8% and 19.2%, respectively. Haplotype analyses of the three single nucleotide polymorphisms inside the PTC gene allowed to identify only two haplotypes that were associated with the non-taster phenotype (100% AVI homozygous) and the taster phenotype (49% PAV homozygous and 51% PAV/AVI heterozygous).
CONCLUSION
There was strong concordance between non-tasters defined by phenylthiocarbamide threshold and AVI homozygous by genotype in normal volunteers.