Co-occurrence of three different mutations in the bilirubin UDP-glucuronosyltransferase gene in a Chinese family with Crigler-Najjar syndrome type I and Gilbert's syndrome

Background. Enzymopathic jaundices are manifested by intermittent hyperbilirubinemia, no changes in the structure of the liver, no hemolysis, Rh-conflict as well as cholestasis being noted. These jaundices include Crigler-Najjar syndrome type I, Crigler-Najjar syndrome type II and Gilbert's syndrome. They are characterized by an autosomal recessive inheritance due to the presence of mutations and polymorphisms in uridine 5'-diphosphate-glucuronosyltransferase gene (UGT1A1) leading to a decrease of the enzyme activity or to its complete loss. Objective. To demonstrate the peculiarities of diagnosis and treatment of a rare case of hereditary unconjugated hyperbilirubinemia - a combination of Crigler-Najjar syndrome type II and Gilbert's syndrome. Material and methods. Clinical observation of a patient G. aged 19, who was examined and treated at the Department of gastroenterology of a multidisciplinary hospital in Moscow in January 2021. Results. The patient G. has had icteric sclerae and skin since birth; he occasionally suffers from easy fatigability and general malaise. Physical examination revealed no changes (except for icteric discoloration). An increase in unconjugated bilirubin up to 270 μmol/L (median - 170 μmol/L) was detected. The molecular genetic study of UGT1A1 gene identified mutations in exon 4 Val378Asp (2002) and Arg108Cys as well as polymorphism 6/7TA in the promoter region, confirming the diagnosis of autosomal recessive inherited disease – a combination of Crigler Najjar syndrome type II and Gilbert's syndrome (heterozygous state), complicated by the development of hepatic encephalopathy stage 2. There was noted a significant decrease in unconjugated bilirubin up to 170.5 μmol/L, as well as improvement in general condition – reduced fatigue and weakness during the treatment with microsomal enzyme inducer (phenobarbital) and hyperammonemia corrector (ornithine aspartate). Conclusions. The use of molecular genetic analysis allows tailoring strategies for patient-specific disease diagnostics, treatment and prevention. The preservation of quality of life within satisfactory level is achieved through elimination of adverse effects provoking the development of this syndrome and through control of risk factors.

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Two Different UGT1A1 Mutations causing Crigler–Najjar Syndrome types I and II in an Iranian Family

Journal of Gastrointestinal and Liver Diseases ◽

10.15403/jgld.2014.1121.244.ugt ◽

2015 ◽

Vol 24 (4) ◽

pp. 523-526 ◽

Cited By ~ 1

Author(s):

Yoshihiro Maruo ◽

Mahdiyeh Behnam ◽

Shinichi Ikushiro ◽

Sayuri Nakahara ◽

Narges Nouri ◽

...

Keyword(s):

Serum Bilirubin ◽

Total Serum Bilirubin ◽

Total Serum ◽

Compound Heterozygous ◽

Type I ◽

Syndrome Type ◽

Type Ii ◽

Wild Type ◽

Iranian Family ◽

Udp Glucuronosyltransferase

Background: Crigler–Najjar syndrome type I (CN-1) and type II (CN-2) are rare hereditary unconjugated hyperbilirubinemia disorders. However, there have been no reports regarding the co-existence of CN-1 and CN-2 in one family. We experienced a case of an Iranian family that included members with either CN-1 or CN-2. Genetic analysis revealed a mutation in the bilirubin UDP-glucuronosyltransferase (UGT1A1) gene that resulted in residual enzymatic activity.Case report: The female proband developed severe hyperbilirubinemia [total serum bilirubin concentration (TB) = 34.8 mg/dL] with bilirubin encephalopathy (kernicterus) and died after liver transplantation. Her family history included a cousin with kernicterus (TB = 30.0 mg/dL) diagnosed as CN-1. Her great grandfather (TB unknown) and uncle (TB = 23.0 mg/dL) developed jaundice, but without any treatment, they remained healthy as CN-2. Results: The affected cousin was homozygous for a novel frameshift mutation (c.381insGG, p.C127WfsX23). The affected uncle was compound heterozygous for p.C127WfsX23 and p.V225G linked with A(TA)7TAA. p.V225G-UGT1A1 reduced glucuronidation activity to 60% of wild-type. Thus, linkage of A(TA)7TAA and p.V225G might reduce UGT1A1 activity to 18%–36 % of the wild-type. Conclusion: Genetic and in vitro expression analyses are useful for accurate genetic counseling for a family with a history of both CN-1 and CN-2. Abbreviations: CN-1: Crigler–Najjar syndrome type I; CN-2: Crigler–Najjar syndrome type II; GS: Gilbert syndrome; UGT1A1: bilirubin UDP-glucuronosyltransferase; WT: Wild type; TB: total serum bilirubin.

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