Variations in the UDP-glucuronosyltransferase 1A1 gene for the development of unconjugated hyperbilirubinemia in Taiwanese

Introduction: Results of several studies have indicated that the variation of c.-3279T>G in the UDP-glucuronosyltransferase (UG7)1A1 gene could be a further factor for the development of hyperbilirubinemia. However, this variant has not been reported in the Taiwanese population. Materials & methods: PCR-restriction fragment length polymorphism was utilized to determine variants at nucleotides -3279 (*60), -53 (*28) and 211 (*6) in the UGT1A1 gene for 178 Taiwanese hyperbilirubinemic patients and 200 controls. Results: A total of ten and nine diplotypes were observed in the hyperbilirubinemic patients and controls, respectively. Subjects possessing diplotypes of compound haplotypes (*60/*28, *60/*6, *1/*60 plus *1/*28 plus *1/*6); *60/*60; *60/*60 plus 1/*28 and *6/*6 were significantly related to hyperbilirubinemia development, with an odds ratio of 7.83-188.00 (p = 0.012 similar to <0.001). A subgroup possessing diplotypes of *60/*60 plus *28/*28 were only found in hyperbilirubinemic patients, not in the controls. Bilirubin concentration amongst these patients carrying a diplotype of *60/*60 plus *28/*28 (mean [SD]: 39.2 [10.77] mu mol/1) was significantly higher than that in the diplotype subgroups of *60/*60 plus *1/*28 (30.4 [4.10] mu mol/l) and *61*6 (30.3 [3.08] mu mol/l) (p = 0.046 and 0.034, respectively). Conclusions: The c.-3279T>G variant is a further factor for the development of hyperbilirubinemia. Our results also demonstrate that possessing the *60/*60 plus *28/*28 diplotype in the UGT1A1 gene is a determinant of relatively higher bilirubin values amongst hyperbilirubinemic patients.