Research advances in the treatment of Crigler-Najjar syndrome / 临床肝胆病杂志

Crigler-Najjar syndrome (CNS) is an autosomal recessive disorder in which the content of plasma unconjugated bilirubin is increased due to the reduction or complete deficiency of the activity of bilirubin uridine diphosphate glucuronosyl transferase 1A1 (UGT1A1), classified as CNS type Ⅰ and Ⅱ. CNS type Ⅰ is the most severe, which will develop into kernicterus, damage the brain nervous system, and even threaten the life of patients. This article introduces six CNS treatment techniques, including phototherapy, plasma exchange, drug therapy, liver transplantation, hepatocyte transplantation and gene therapy. The applicable patient types, treatment effects and existing deficiencies of each technique were summarized. Phototherapy, plasma exchange, drug therapy and hepatocyte transplantation can temporarily control serum levels and reduce the risk of jaundice, but cannot completely restore UGT1A1 enzyme activity; liver transplantation is currently the only treatment option for CNS type Ⅰ patients, but is limited by suitable liver donors and post-operative immune rejection. Gene therapy has the most promising application in the treatment of genetic disorders such as CNS, which can provide more viable therapeutic techniques for CNS patients.

Crigler-Najjar Syndrome Type 2 in an Adult: A Rare Presentation

Introduction: Crigler-Najjar syndrome type 2 (CNS type 2) is a rare disorder that causes elevated levels of bilirubin in the blood (nonhemolytic unconjugated hyperbilirubinemia). The main symptom of CNS type 2 is persistent jaundice. It is caused by genetic changes in the UGT1A1 gene and the inheritance is autosomal recessive. Genetic testing of the UGT1A1 gene for mutations is the diagnostic clincher. We report one such rare case. Case report: A 75-year-old male presented with history of right-sided weakness with right-sided facial weakness, MRI brain revealed an infarct in the left side of brain with general physical findings suggestive of icterus. Conclusion: Diagnosing and managing these patients may be challenging. Our aim is to draw attention of the treating physicians towards this disease with the help of this case report.

UGT1A1 gene polymorphisms in patients with Gilbert syndrome and Crigler-Najjar syndrome type Ⅱ / 临床肝胆病杂志

Objective To investigate the differences in UGT1A1 gene mutation sites, haplotypes, and diplotypes between patients with Gilbert syndrome (GS) and those with Crigler-Najjar syndrome type Ⅱ (CN-2). Methods A retrospective analysis was performed for the clinical data of 138 patients with GS or CN-2 who attended Beijing YouAn Hospital, Capital Medical University, from January 1, 2010 to December 31, 2019, with 109 patients in the GS group and 29 patients in the CN-2 group, and the differences in mutation sites were analyzed between the two phenotypes. The Mann-Whitney U test was used for comparison of continuous data between two groups, and the chi-square test or the Fisher's exact test was used for comparison of categorical data between groups. SNPStats software was used to perform linkage disequilibrium (LD) and haplotype analyses of mutation sites. Strong LD was defined as both | D ′| and r 2 > 0.8, and moderate LD was defined as | D ′| > 0.8 and r 2 > 0.4. Results UGT1A1 gene detection was performed for all patients, and mutations mainly included -3279T > G mutation (104 patients, 75.36%) and -3152G > A mutation (82 patients, 59.42%) in the upstream promoter PBREM region, a promoter TATA box TA insertion mutation (88 patients, 63.77%), and c.211G > A mutation in Exon 1 of the coding region (66 patients, 47.83%). Compared with the CN-2 group, the GS group had a significantly higher proportion of PBREM region -3279T > G mutation (82.57% vs 48.28%, χ 2 =14.508, P A mutation (68.81% vs 24.14%, χ 2 =18.955, P (TA) 7 mutation (72.48% vs 31.03%, χ 2 =17.027, P 0.8, r 2 > 0.8) between (TA) 6 > (TA) 7 and -3152G > A and moderate LD (| D ′| > 0.8, r 2 > 0.4) between (TA) 6 > (TA) 7 and -3279T > G, between -3152G > A and -3279T > G, between (TA) 6 > (TA) 7 and c.211G > A, and between -3279T > G and c.211G > A. Haplotype frequency analysis showed that compared with the CN-2 group, the GS group had a significantly higher frequency of haplotype -3279G—-3152A—(TA) 7 (45.72% vs 17.24%, χ 2 =7.833, P =0.005) and significantly lower frequencies of c.1456G (4.10% vs 16.48%, χ 2 =4.873, P =0.027) and c.211A—c.1456G (1.86% vs 24.90%, χ 2 =15.210, P < 0.001). The diplotype analysis showed that diplotypes consisting of haplotype c.1456G or c.211A—c.1456G were associated with a higher level of total bilirubin (TBil). Conclusion There are differences in common mutation sites and major haplotypes of the UGT1A1 gene between patients with GS and those with CN-2, and the common diplotypes of CN-2 correspond to a higher level of TBil.

Research advances in congenital non-hemolytic jaundice / 临床肝胆病杂志

Congenital non-hemolytic jaundice is an important type of jaundice diseases, and except breast milk jaundice, the other types of this disease are relatively rare in clinical practice. Most of them belong to genetic and metabolic liver diseases, including Gilbert syndrome, Crigler-Najjar syndrome, and Lucey-Driscoll syndrome with an increase in unconjugated bilirubin and Dubin-Johnson syndrome and Rotor syndrome with an increase in conjugated bilirubin. With reference to the recent literature in China and foreign countries, this article reviews the pathogenesis, genetic characteristics, diagnosis, treatment, and differential diagnosis of six types of hereditary congenital unconjugated jaundice.

Living related donor liver transplantation for infant with Crigler-Najjar syndrome type Ⅰ: a report of one case and literature review / 器官移植

Objective To summarize the therapeutic effects of living related donor liver transplantation for Crigler-Najjar syndrome type Ⅰ (CNS type Ⅰ). Methods A 3-month-old male infant had appeared a progressive xanthochromia of the skin and sclera 4 d after birth without obvious cause. Other causative factors were eliminated after relevant tests were completed, and identified as CNS type Ⅰ by genetic testing. Living related donor liver transplantation was performed with his mother as the donor. An immunosuppression regimen was routinely applied postoperatively and tacrolimus doses were adjusted according to biochemical indicators and cytochrome P450 (CYP) 3A5 genotype of the recipient. Results The liver enzymes of the recipient returned to normal at 7 d postoperatively, and bilirubin decreased daily and fell to the normal range at 22 d postoperatively. Followed up to the submission date, the recipient's xanthochromia of skin and scleral faded with normal bilirubin and stable liver enzymes. The condition of the recipient was generally good with high quality of life. Conclusions Living donor liver transplantation can treat unconjugated hyperbilirubinemia and other diseases caused by CNS type Ⅰ, which greatly improve the quality of life of patients.

Hiperbilirrubinemias hereditarias: un diagnóstico diferencial a considerar en ictericia / Hereditary hiperbilirrubinemias: a differential diagnosis to considerer in icterus

Las hiperbilirrubinemias hereditarias (HBH) son patologías originadas por defectos en las enzimas y proteínas que participan del metabolismo de la bilirrubina. El clearence de bilirrubina incluye captación y almacenamiento en hepatocitos, conjugación, excreción hacia la bilis y recaptura de su forma conjugada por hepatocitos. Las HBH varían de acuerdo a su patogenia, presentación clínica, niveles de bilirrubinemia y tratamientos disponibles. En general son poco frecuentes, a excepción del Síndrome de Gilbert. Están las que son de predominio indirecto, como el Síndrome de Gilbert y el de Crigler-Najjar, y las de predominio directo, como el Síndrome de Dubin-Johnson y el de Rotor. En general no requieren tratamiento específico y tienen curso benigno, a excepción del Síndrome de Crigler-Najjar para el cual existen medidas terapéuticas específicas a considerar, teniendo un pronóstico reservado para algunas de sus formas de presentación. Es importante el conocimiento de estos síndromes dado el alto índice de sospecha requerido para su diagnóstico y para su diferenciación de otras patologías hepatobiliares de mayor riesgo y severidad.

Hereditary hiperbilirrubinemias (HBH) are pathologies originated from the defect of the enzymes and proteins involved in the metabolism of bilirubin. The bilirubin clearance includes uptake and storage in hepatocytes, conjugation, excretion into bile and recapture of its conjugated form by hepatocytes. HBH vary according to their pathogenesis, clinical presentation, levels of bilirubin and available treatments. Generally they are infrequent, except for Gilbert Syndrome. There are those with indirect bilirubin predominance, such as Gilbert and Crigler-Najjar syndromes, and those with direct bilirubin predominance, including Dubin-Johnson and Rotor syndromes. In general, they do not require specific treatment and have a benign course, with the exception of the Crigler-Najjar Syndrome, for which there are specific therapeutic measures to consider, as well as a reserved prognosis for some of their forms of presentation. The knowledge of these syndromes is important 2 given the high index of suspicion required for its diagnosis and for its differentiation from other hepatobiliary pathologies of greater risk and severity.

Study on spectrum of UGT1A1 mutations in connection with inherited non-hemolytic unconjugated hyperbilirubinemia / 中华肝脏病杂志

Objective@#To compare and analyze patient’s general condition, changes in laboratory parameters, and the spectrum of UGT1A1 mutations in patients with inherited non-hemolytic unconjugated hyperbilirubinemia.@*Methods@#A retrospective study was conducted at Nanjing Second Hospital from January 2015 to July 2018 and patients’ demographic characteristics, liver function test, and UGT1A1 gene were analyzed. The categorical variable data were compared by χ 2 test. The normal distribution continuous variable data were compared by t-test and the non-normal distribution continuous variable data were compared using Mann-Whitney U test.@*Results@#Of the 51 patients with inherited non-hemolytic unconjugated hyperbilirubinemia, 44 (86.3%) were Gilbert’s syndrome (GS) and seven (13.7%) were Crigler-Najjar syndrome type II (CNS- II). The male to female ratio was 2.9:1 and the average age was 36.11 ± 13.17 years. Six variant types were detected: C. -40_-39insTA, C. -3279T > G, c.211G > A (p.G71R), c.686C > A (p.P229Q), c.1091C > T (p.P364L), c.1456T > G (P.Y486D). Among them, c.211G > A accounted for 58.82% (30/51), c.-40_-39insTA accounted for 27.5% (14/51), and c.1456T > G accounted for 25.5% (13/51). The total bilirubin(TB) and unconjugated bilirubin (UCB) in CNS-II patients were significantly higher than GS patients[155.91 (130 ~ 207) vs. 38.25(29 ~ 52.15) μmol/L, U = 0, P < 0.01; 144.13 (120.8 ~ 197) vs. 30.00 (21.7 ~ 46.75) μmol/L, U = 0.00, P < 0.01, respectively]. Exon mutations of c.1091C > T and c.1456T > G were statistically significant(P < 0.01).There were no differences in age, TB, UCB, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) between the c.211G > A homozygous variants and heterozygous variants (P > 0.05).@*Conclusion@#The common pathogenic mutations of UGT1A1 gene were c.211G > A, c.-40_-39insTA, c.1456T > G. c.211G > A. The mutation has little effect on the level of total bilirubin, but c.1091C > T, c.1456T > G mutations has great influence on the level of total bilirubin.

Síndrome Lucey-Driscoll - Reporte de caso / Lucey-Driscoll Syndrome - Case Report

La hiperbilirrubinemia no conjugada es una condición producida por una alteración en el proceso de conjugación y excreción de la bilirrubina. La glucoronosiltransferasa uridin difosfato es la responsable en la conjugación de la bilirrubina, es codificada por el gen de UGT1A1 localizado en el brazo q del cromosoma 2 locus 37.1. La variación genética del UGT1A1 puede producir diferentes fenotipos desde el más severo llamado Sindrome Crigler-Najjar Tipo I y II, pasando por el Sindrome de Gilbert; hasta una hiperbilirrubinemia transitoria neonatal o síndrome LUCEY-DRISCOLL (HBLRTFN) fenotipo OMIM 237900 con producción de kernicterus y parálisis cerebral pero con resolución espontánea, todos ellos de herencia autosómica recesiva causada por mutación homocigota o heterocigota en el gen UGT1A1. En este reporte se presenta un caso en un recién nacido que a los 7 días presenta hiperbilirrubinemia severa con kernicterus, y la prueba genética muestra mutación heterocigota del *28 del gen UGT1A1

Unconjugated hyperbilirubinemia is produced by alteration in conjugation and excretion process of bilirubin. Glucoronosiltransferasa Uridine diphosphate enzyme is involved in bilirubin conjugation. Is encoded by the UGT1A1 gene located in chromosome 2q locus 37.1. UGT1A1 genetic variation can produce different phenotypes Crigler-Najjar Syndrome Type I and II, Gilbert Syndrome, and hyperbilirubinemia transited familial LUCEY-DRISCOLL (HBLRTFN) syndrome with kernicterus production but with spontaneous resolution, all autosomal recessive. We present here a case of newborn 7 days old with severe hyperbilirubinemia , kernicterus, and genetic testing shows heterozygous mutation of the UGT1A1 * 28 gene

The establishment of a high resolution melting analysis based rapid screening system for UGT1A1 gene mutation / 中华检验医学杂志

Objective To develop a high-resolution melting ( HRM ) assay for rapidly screening Gilbert syndrome ( GS) and Crigler-Najjar syndrome ( CNS) associated with UGT1A1 defects.Method Methodology was developed .Then, we applied the established method to analyze 61 clinical samples from neonatal patients with severe unexplained unconjugated hyperbilirubinemia .Neonates with known risk factors for developing hyperbilirubinemia , such as ABO hemolysis, G6PD deficiency, sepsis, hypoxic ischemic encephalopathy were excluded .Five pairs of PCR primers were designed to detect the five common mutations (G211A, C686A, C1091T, C1352T and T1456G) in Asia population.PCR and HRM Assay conditions were optimized.UGT1A1 genotyping in clinical samples was performed by using the established HRM analysis , and all results were subsequently confirmed by direct DNA sequencing .Results The mutants were readily differentiated by using HRM analysis .In this study, 42 neonates were identified with UGT1A1 mutation, and 4 different known variants were detected .Conclusion HRM analysis in this study was economical, convenient, rapid, effective for screening UGT1A1 gene mutations, which can serve as an reliable method for the clinical diagnosis of GS and CNS and the large-scale molecular epidemiological research of UGT1A1 gene-related diseases.

Genetic analysis and literature review of Crigler-Najjar syndrome typeⅠ / 临床儿科杂志

ObjectiveTo analyze the Uridine diphosphoglucuronyl transferase 1 A1 gene (UGT1A1) mutation in non-he-molytic indirect hyperbilirubinemia.MethodsA female patient was diagnosed with type I Crigler-Najjar syndrome (CNS-I) after excluding hemolysis and hypothyroidism. Phototherapy treatment is effective while oral phenobarbital was not. UGT1A1 were ampliifed by polymerase chain reaction and DNA was sequenced.ResultsThe patient was compound heterozygote of c.1070A>G p. (Gln357Arg) and 1091C>T p. (pro364Leu) and diagnosed with CNS-I. Heterozygotes of the mutation were found in her parents.ConclusionsIn patients highly suspected of CNS, the genetic tests should be carried out as soon as possible.

Síndrome de Crigler-Najjar tipo 2 ? um caso atípico / Crigler-Najjar syndrome type 2 ? an atypical case

Objetivos: Os autores descrevem um caso de síndrome de Crigler-Najjar tipo 2, um distúrbio hereditário do metabolismo da bilirrubina, resultante de um déficit parcial da enzima uridino-difosfo-glicuronil-transferase (UDPG T).Descrição do caso: Uma lactente de etnia asiática foi internada com cinco semanas de vida por icterícia persistente desde o nascimento, com relato materno de agravamento progressivo. Ao exame objetivo apresentava-se ativa, reativa, ictérica e com ligeira hipotonia axial. A investigação complementar mostrou um aumento da bilirrubina total (32,94 mg/dL), com bilirrubina direta de 0,94 mg/dL, e o estudo molecular revelou duas mutações em heterozigotia no gene UGT1A1 (c.211G>A e c.1456T>G), resultado compatível com síndrome de Crigler-Najjar tipo 2. Foi submetida a fototerapia intensiva em associação com quelante dos ácidos biliares, com resposta parcial. Após conhecimento do resultado do estudo molecular iniciou fenobarbital, ocorrendo normalização dos valores de bilirrubina após duas semanas.Conclusões: A síndrome de Crigler-Najjar tipo 2, embora fenotipicamente semelhante ao tipo 1, tem tratamento e prognóstico diferentes. Neste caso, a apresentação neonatal precoce e os valores de bilirrubina muito elevados, que não cediam totalmente à fototerapia intensiva, levaram inicialmente à suspeita de síndrome de Crigler-Najjar tipo 1, que é a forma mais grave. Os autores pretendem com este caso alertar para uma causa rara de icterícia, que não teve a apresentação típica.

Aims: The authors describe a case of Crigler-Najjar syndrome type 2, an inherited disorder of bilirubin metabolism resulting from a partial deficit of the enzyme uridine- diphospho-glucuronyl transferase (UDPG-T).Case description: A female infant of Asian ethnicity was admitted with five weeks of age by persistent jaundice since birth, with maternal report of progressive worsening. Upon physical examination the patient was active, reactive, and jaundiced, with mild axial hypotonia. Complementary examination showed increase in total bilirubin (32.94 mg/dL), with direct bilirubin of 0.94 mg/dL, and molecular study revealed two heterozygous mutations in the UGT1A1 gene (c.211G>A and c.1456T>G), consistent with Crigler-Najjar syndrome type 2. She was submitted to intensive phototherapy in combination with bile acid chelator, with a partial response. After reading the results of molecular studies, phenobarbital was started, leading to normal levels of bilirubin in two weeks.Conclusions: Crigler-Najjar syndrome type 2, although phenotypically similar to type 1, has different prognosis and treatment. In this case, early neonatal presentation and very high bilirubin values not fully yielded to intensive phototherapy, initially raised the suspicion of Crigler-Najjar syndrome type 1, which is the most severe form of the syndrome. With this report, the authors wish to draw attention to a rare cause of jaundice, which did not have its typical course.

Evolución prolongada en síndrome de Crigler-Najjar tipo I / Crigler-Najjar syndrome. Report of one case with a long term follow up

Crigler-Najjar Syndrome is an uncommon genetic disorder characterized by the elevation of unconjugated plasmatic bilirubin secondary to deficiency of the enzyme uridine diphosphate glucuronyltransferase (UDP-GT). We report a 19-years-old woman with the syndrome diagnosed during the neonatal period, when she developed a severe jaundice in the first 10 days of life, reaching unconjugated bilirubin levels of 29 mg/dl, with normal liver function tests. After transient response to phototherapy, the patient was referred to a tertiary medical center in which an extensive work up ruled out other etiologies and the diagnosis of type I Crigler-Najjar syndrome was established. Currently, the patient has a mild mental retardation. She is receiving homemade phototherapy 18 h per day with acceptable control of bilirubin levels. Many mutations have been associated with UDP-GT dysfunction resulting in a broad spectrum of the disease. When bilirubin rises above physiological limits, it permeates the hematoencephalic barrier, inducing bilirubin impregnation of basal ganglia with secondary neuronal damage and necrosis. The worst outcome, kernicterus, is characterized by mental retardation, central deafness, ophthalmoplegia, ataxia, athetosis, spasticity, seizures and death. First line therapy includes phototherapy, but definitive therapy is liver transplantation before the occurrence of neurological damage.

Molecular Analysis of the UGT1A1 Gene in Korean Patients with Crigler-Najjar Syndrome Type II / 대한소아소화기영양학회지

PURPOSE: Crigler-Najjar syndrome type II (CN-2) is characterized by moderate non-hemolytic unconjugated hyperbilirubinemia as a result of severe deficiency of bilirubin uridine diphosphate-glucuronosyltransferase (UGT1A1). The study investigated the mutation spectrum of UGT1A1 gene in Korean children with CN-2. METHODS: Five Korean CN-2 patients from five unrelated families and 50 healthy controls were enrolled. All five exons and flanking introns of the UGT1A1 gene were amplified by polymerase chain reaction (PCR) and the PCR products were directly sequenced. RESULTS: All children initially presented with neonatal jaundice and had persistent indirect hyperbilirubinemia. Homozygous p.Y486D was identified in all five patients. Three patients had an associated homozygous p.G71R and two a heterozygous p.G71R. The allele frequency of p.Y486D and p.G71R in healthy controls was 0 and 0.16, respectively. No significant difference in mean serum bilirubin levels was found between homozygous carriers of p.G71R and heterozygous carriers. CONCLUSION: The combination of homozygous p.Y486D and homozygous or heterozygous p.G71R is identified. The p.Y486D and p.G71R can be screened for the mutation analysis of UGT1A1 in Korean CN-2 patients.

Genetic analysis of UGT1A1 gene in a case and her family members with Crigler-Najjar syndrome type Ⅰ / 中华实用儿科临床杂志

Objective To test the mutation locus of uridine diphospho-glucuronosyltransferase gene (UGT1A1) in a Chinese patient with Crigler-Najjar syndrome type Ⅰ and her family members,analyzing the genetic characteristics of the pedigree.Methods Genomic DNA was extracted from the patient and her family members and other 50 full-term infants with normal serum bilirubin as a healthy control group.Fifty cases of full-term newborn whose serum bilirubin level were nomal were study as controls.The promoter and all exons of UGT1A1 gene were amplified by the method of polymerase chain reactions (PCR),and mutations were identified by direct sequencing.Results The propositus and her miscarriage sister were homozygous for a nonsense mutation at nucleotide number 715 (715C ＞ T) in exon 1 of gene UGT1A1,substituting of stop codon (TAG) for glutamine (CAG) at position 239 (Q239X).The other 5 members were heterozygous in the same mutation locus.A TA insertion mutation and a G71R mutation in exon 1 were observed in the family members.The patient and her sister were homozygous of A(TA)7TAA mutation while other four were heterozygous.Propositus,grandmother,mother and her younger brother were heterozygous of G71 R mutation.No mutation was found in exons 2-5.No mutation was found in other fifty healthy cases in the healthy control group.Conclusions Q239X homozygous mutations is considered to be the lethal gene in this Crigler-Najjar syndrome family.Collaborative G71 R and A(TA)7TAA mutations may further reduce the enzyme activity of UGT1A1,causing varying degrees of bilirubin disorder.

Crigler-Najjar syndrome type 2: Novel UGT1A1 mutation.

Crigler-Najjar syndrome type 2 is a rare cause for persistent unconjugated hyperbilirubinemia, inherited in an autosomal recessive manner. Even though it is compatible with normal life span, in the absence of prompt suspicion and intensive management it can prove fatal not only in the neonatal period but also during adult life. Here, we describe a case with a novel homozygous UGT1A1 p.Pro176Leu mutation.

Hereditary Spherocytosis Coexisting with UDP-Glucuronosyltransferase Deficiency Highly Suggestive of Crigler-Najjar Syndrome Type II

Patients with co-existing hereditary spherocytosis (HS) and UDP-glucuronosyltransferase 1A1 (UGT1A1) deficiency as Gilbert's syndrome (GS) have been reported, and previous studies have demonstrated an increased risk for developing gallstones in patients with co-inheritance of GS and HS. We experienced an interesting case of HS showing persistent jaundice after splenectomy, and upon further evaluation, the 25-year-old female patient was found to have HS combined with UGT1A1 deficiency. Sequence analysis of the UGT1A1 gene revealed that she was a compound heterozygote with p.[G71R; Y486D] + [Y486D] mutations, which suggests Crigler-Najjar syndrome type II rather than GS. Careful evaluation of inappropriately elevated bilirubin level compared with the degree of hemolysis is important, reflecting the therapeutic implication of splenectomy and cholecystectomy.

A Case of Crigler-Najjar Syndrome Type 2 Diagnosed Using Genetic Mutation Analysis / 대한소아소화기영양학회지

Crigler-Najjar syndrome is a rare inherited disease associated with unconjugated hyperbilirubinemia. It is inherited via an autosomal recessive pattern and is caused by mutation in one of the five exons of the bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (UGT1A1) gene. The synthesis of inactive isoforms of bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (B-UGT) results in unconjugated hyperbilirubinemia. A 13-year-old boy with jaundice for 4 months was admitted to our hospital. He had unconjugated hyperbilirubinemia with no evidence of infection, hemolysis, or structural abnormalities on abdominal ultrasonography or 99mTc-DISIDA scan. The authors identified a missense mutation of Tyr486Asp in the fifth exon of the UGT1A1 gene and diagnosed the patient with Crigler-Najjar syndrome type II. This is the first reported case of Crigler-Najjar syndrome in a Korean child, and it is also the first reported case of a genetic mutation leading to Crigler-Najjar syndrome in Korea.

A Case of Crigler-Najjar Syndrome Type 2 Diagnosed Using Genetic Mutation Analysis / 대한소아소화기영양학회지

Crigler-Najjar syndrome is a rare inherited disease associated with unconjugated hyperbilirubinemia. It is inherited via an autosomal recessive pattern and is caused by mutation in one of the five exons of the bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (UGT1A1) gene. The synthesis of inactive isoforms of bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (B-UGT) results in unconjugated hyperbilirubinemia. A 13-year-old boy with jaundice for 4 months was admitted to our hospital. He had unconjugated hyperbilirubinemia with no evidence of infection, hemolysis, or structural abnormalities on abdominal ultrasonography or 99mTc-DISIDA scan. The authors identified a missense mutation of Tyr486Asp in the fifth exon of the UGT1A1 gene and diagnosed the patient with Crigler-Najjar syndrome type II. This is the first reported case of Crigler-Najjar syndrome in a Korean child, and it is also the first reported case of a genetic mutation leading to Crigler-Najjar syndrome in Korea.