UGT1A1 and Hyperbilirubinemia: Aims of this study were to quantitatively analyze the UGT1A1 genotype–phenotype correlation among Chinese children with unconjugated hyperbilirubinemia, to elucidate the clinical significance of complex UGT1A1 genotypes that occurred in a single patient (multiple SNPs, SNP plus mutation, and multiple mutations), and to expand UGT1A1 variant spectrum by discovering novel mutations or variants.