GENETIC POLYMORPHISM IN THE PHENOBARBITAL-RESPONSIVE ENHANCER MODULE OF THE UDP-GLUCURONOSYLTRANSFERASE 1A1 GENE IN VIETNAMESE

Abstract

UDP glucurosyltransferase 1 family polypeptide A1 (UGT1A1) is the enzyme in the liver that is responsible for bilirubin glucuronidation. Mutation altering nucleotide sequence in the coding region, enhancermodule or promoter region can affect enzyme function or structure. UGT1A1*60 is a T-to-G substitution at nucleotide -3279 in the phenobarbital-responsive enhancer module of UGT1A1 gene, which reduces the transcription activity of UTG1A1 gene. To determine the present of UTG1A1*60 variant in Vietnamese population, we used the direct sequencing method of PBREM fragment of UTG1A1 gene to determine the genotype and its allele frequency in 96 individuals of healthy Kinh ethnic group. The results showed that UTG1A1*60 variant is present in homozygousand heterozygous genotypes with frequencies of 45.833% (N = 44) and 9.375%, respectively. The allele frequency of the UTG1A1*60 variant in the population was quite high (32.292%). This study contributes to the understanding of the genetic characteristics of the UGT1A1 gene in the Vietnamese population and shows a remarkable role of this variant in the hyperbilirubinemia patients.