UGT1A1 and Hyperbilirubinemia: Moreover, heterozygous and/or homozygous UGT1A1 mutations in the coding sequence region were significantly associated with the increased risk of developing hazardous hyperbilirubinemia (as defined by TSB > 427 umol/L) as compared those with a normal UGT1A1 genotype (ORadj = 9.16, 95%CI 1.99–42.08, P = 0.002) in the study cohort.