Polymorphism of UDP-glucuronosyltransferase Gene(UGT1A1) of Neonatal Hyperbilirubinemia in Korea

Hong, Ki Woong; Kang, Hoon; Kim, Il Soo; Kim, Ji Sook; Kim, Eun Ryoung; Lee, Hee Jae; Jin, Sheng Yu; Chung, Joo Ho

Abstract

PURPOSE
The incidence of neonatal hyperbilirubinemia is twice as high in East Asians as in whites and its metabolic basis has not been clearly explained. Recently, UDP-glucuronosyltransferase gene (UGT1A1) mutation was found to be a risk factor of neonatal hyperbilirubinemia in Japanese and Taiwanese Chinese. We studied whether neonatal hyperbilirubinemia is associated with mutation of UGT1A1, which is a key enzyme of bilirubin catabolism, in Korean.
METHODS
The genomic DNA was isolated from 45 Korean full term neonates who had hyperbilirubinemia(serum bilirubin >12 mg/dL) with no obvious causes, and the 64 Korean neonates of the control population. We detected a missense mutation of Gly71Arg of UGT1A1 gene by using allele-specific polymerase chain reaction. Polymorphism was confirmed by direct sequencing.
RESULTS
Two of the 45 neonates with serum bilirubin above 12 mg/dL had homozygous mutation and 16 neonates had heterozygous mutation. Two of the 31 neonates with serum bilirubin above 15 mg/dL had homozygous mutation and 13 neonates had heterozygous mutation. Thirteen of the control group had heterozygous mutation and homozygous mutation was not found. Allele frequency of Gly71Arg mutation in hyperbilirubinemia group was 0.22, which was significantly higher than 0.11 in the control group(P<0.0144).
CONCLUSION
The missense mutation causing Gly71Arg of UGT1A1 was detected in the Korean neonatal hyperbilirubinemia. The high frequency of this missense mutation may be attributed to the high prevalence of hyperbilirubinemia in the Korean.