Crigler-najjar syndrome type ii in a chinese boy resulting from three mutations in the bilirubin uridine 5'-diphosphate-glucuronosyltransferase (UGT1A1) gene and a family genetic analysis

Abstract

Background: The UGT1A1 gene encodes a responsible enzyme, UDP-glucuronosyltransferase1A1 (UGT1A1), forbilirubin metabolism. Many mutations have already been identified in patients with inherited disorders withunconjugated hyperbilirubinemia, such as Crigler-Najjar syndromes and Gilbert's syndrome.Case presentation: In this report, we presented a boy with intermittent unconjugated hyperbilirubinemia, whosegenetic analysis showed a new compound heterozygote determined by three mutations, c.211G > A (p.G71R),c.508_510delTTC (p.F170-) and c.1456 T > G (p.Y486D) in the hotspot regions of the UGT1A1 gene (exons 1 and 5)in Asian populations, presenting a genotype compatible with clinical picture of CNS-II. The family genetic analysisconfirmed the origin of these mutations.Conclusion: UGT1A1 gene analysis should be performed in all cases with unexplained unconjugatedhyperbilirubinemia. The description of patients with peculiar genotypes especially including family analysis couldhelp explain the relationship between the genotype and phenotype,it is helpful for clinicians to predict theoutcome of the patients.