UGT1A1 and Hyperbilirubinemia: Moreover, Chen et al. [26] reported that homozygous UGT1A1*28 and homozygous UGT1A1*6 are associated with increased risk of hyperbilirubinemia, in which the odds ratio is 17.79 for UGT1A1*28 and 14.93 for UGT1A1*6.