UGT1A1 and Hyperbilirubinemia: On the contrary, after adjusted by age, gender, and feeding method, ABO HDNs with heterozygous and/or homozygous mutations in the UGT1A1 coding sequence region had a relatively higher risk of developing hazardous hyperbilirubinemia than those with a normal UGT1A1 genotype (ORadj = 9.16, 95%CI 1.99–42.08, P = 0.002).