新生儿高未结合胆红素血症遗传因素的研究

目的：探讨尿苷二磷酸葡萄糖醛酸转移酶1A1（UGT1A1）Gly71Arg、TATA盒基因突变和葡萄糖-6-磷酸脱氢酶（G6PD）基因突变与新生儿高未结合胆红素血症的关系。方法：UGT1A1 TATA盒、外显子1、外显子5和G6PD基因外显子12经PCR扩增和测序,构建突变样本的克隆,对其进行验证。分析病例组及对照组UGT1A1 Gly71Arg和TATA盒基因多态性频率的差异,应用logistic回归分析基因突变对新生儿高未结合胆红素血症发生的影响。结果：病例组UGT1A1 Gly71Arg基因多态性的基因型分布与对照组比较差异有统计学意义（P0.05）。Logistic回归分析显示UGT1A1 Gly71Arg、TATA盒基因和G6PD基因突变对新生儿高未结合胆红素血症发生的OR值（95％CI）分别为5.468（2.274,12.818）、0.688（0.266,1.778）和5.081（1.070,24.133）。结论：UGT1A1 Gly71Arg和G6PD基因突变可能是新生儿高未结合胆红素血症发生的原因。     

Gilbert's syndrome--a frequent cause of unconjugated hyperbilirubinemia in children after orthotopic liver transplantation

Gilbert's syndrome is one major cause for unconjugated hyperbilirubinemia in healthy individuals with the prevalence being approximately 3.2-8.6%. It is caused by a mutation in the promoter region of the UGT1A1-gene with a prolonged TAA-repeat coding for the enzyme bilirubin UDP-glucuronosyltransferase (A(TA)(7) TAA allele). After OLT, Gilbert's disease of the transplanted liver can cause unconjugated hyperbilirubinemia. Therefore, we looked for the presence of A(TA)(7) TAA alleles in pediatric liver transplant recipients with unconjugated hyperbilirubinemia. Laboratory results of 106 pediatric liver transplant recipients (aged 0-17 yr) were evaluated for elevated total bilirubin over 2.0 mg/dL (conjugated bilirubin <30%). In these patients, DNA of the liver graft was extracted from paraffin-embedded liver biopsy samples formerly taken for diagnostic reasons. The DNA was analyzed for A(TA)(7) TAA alleles in the promoter region of the UGT1A1-gene. In 4 of 106 pediatric liver transplant recipients we found unconjugated hyperbilirubinemia with total bilirubin above 2.0 mg/dL (conjugated bilirubin <30%). The analysis of the promoter region of the UGT1A1-gene of the liver grafts showed three homozygous A(TA)(7) TAA alleles (homozygous Gilbert's syndrome) and one heterozygous A(TA)(7) TAA allele (heterozygous Gilbert's syndrome). This study shows that pediatric liver transplant recipients with unconjugated hyperbilirubinemia are very likely to have received a liver graft from a donor with Gilbert's syndrome.     

广西黑衣壮族高胆红素血症新生儿UGT1A1基因突变分析

目的 探讨广西黑衣壮族高胆红素血症新生儿尿苷二磷酸葡萄糖醛酸转移酶1A1（UGT1A1）基因的突变分布特点及其与高胆红素血症的关系。方法 提取黑衣壮族高胆红素血症新生儿（病例组）及对照组新生儿血液基因组DNA各100例,对UGT1A1 启动子TATA盒及所有外显子进行PCR扩增及直接测序。结果 检测到UGT1A1 启动子TATA盒（TA）7插入突变、第1外显子G71R错义突变及第5外显子中4个SNP位点（rs199539868、rs114982090、rs1042640、rs8330）。病例组的G71R等位基因频率显著高于对照组（PP>0.05）。Logistic回归分析显示UGT1A1 TATA盒、G71R、rs1042640及rs8330对新生儿高胆红素血症发生的OR值（95%CI）分别为0.846（0.440,1629）、3.932（1.745,8.858）、0.899（0.364,2.222）。结论 UGT1A1基因（TA）7插入突变与G71R错义突变是广西黑衣壮族高胆红素血症新生儿的常见突变类型,4个SNP 位点（rs199539868、rs114982090、rs1042640、rs8330）为国内首次报道。UGT1A1 G71R错义突变是广西黑衣壮族新生儿高胆红素血症的危险因素。     

广西三江县侗族新生儿UGT1A1基因变异分析北大核心CSCD

目的探讨广西柳州三江县侗族新生儿UGT1A1基因变异特点及其与侗族新生儿高胆红素血症发生的关系。方法前瞻性选取2021年1月至2022年1月于三江县人民医院新生儿科诊断不明原因高胆红素血症的新生儿84例为研究对象;另选取同期健康新生儿60例纳入健康对照组。提取两组新生儿外周血基因组DNA,对UGT1A1启动子区TATA盒和外显子1进行PCR扩增并进行基因测序。结果病例组检测出33例G71R错义突变,突变率为39%,A等位基因频率(21%)显著高于健康对照组(10%)(P<0.05)。携带G71R错义突变基因型的侗族新生儿发生高胆红素血症的风险是携带野生型的健康新生儿的2.588倍(P<0.05)。Hardy-Weinberg遗传平衡检验结果提示两组新生儿UGT1A1 G71R位点基因型符合遗传平衡(P>0.05)。结论UGT1A1 G71R突变是三江县侗族新生儿高频基因变异类型,且G71R错义突变与侗族新生儿发生高胆红素血症相关。     

Gilbert综合征及其分子遗传学基础

Gilbert综合征是先天性、非溶血性、非结合性高胆红素血症.临床以间歇性轻度黄疸为特征.其发病机制主要是编码尿苷二磷酸葡萄糖苷酸基转移酶同工酶(UGT1A1)基因突变.此基因突变还可影响药物葡萄糖醛酸化,治疗剂量即可发生未预期的毒性.UGT1A1基因的检测对于Gilbert综合征的诊断、治疗和遗传咨询具有重要意义.     

Hiperbilirubinemia noworodków w aspekcie polimorfizmu genu UGT1A1

IntroductionIncreasing number of screening tests is based on human DNA analysis. Diseases yet of unknown etiology prove to have an underlying genetic factor. Understanding of human genome allows improved diagnosis, better choice of farmacotherapy or more adequate lifestyle modifications. Neonate hyperbilirubinemia has been linked to UGT1A1 gene polymorphism. UGT1A1 gene encodes UDP-glucuronosyltransferase, an enzyme that catalyses the addition of bilirubin to glucuronic acid which allows its excretion. Changes in UGT1A1 gene structure are responsible for mild unconjugated hyperbilirubinemia in adults called the Gilbert's syndrome.AimThe objective of this study was to determine the frequency of UGT1A1*28 and *60 gene polymorphism in studied neonate groups as well as to establish the link in specific UGT1A1 gene mutation in neonate hyperbilirubinemia occurrence.Material and methods171 neonates born between November 2008 and January 2009 in Medical University of Gdansk Obstetrics Clinic were included in the study. Studied material included dried up blood stains.ResultsUGT1A1*28 genotype (homozygotic mutation) as well as male sex influence neonate hyperbilirubinemia. P < 0.05.ConclusionsIdentification of UGT1A1 gene polymorphism can explain the causes of neonate hiperbilirubinemia in children with no risk factors. Moreover it would allow individual treatment options. It would also be useful in patients’ development as UDP-glucuronosyltransferase is engaged in metabolism of many widely used drugs. The performed analysis justify further UGT1A1 gene polymorphism studies in Polish population and can be useful in determination of an treatment algorithm for neonates suffering from hiperbilirubinemia.     

Inherited disorders of bilirubin metabolism

Jaundice in an infant or older child may reflect accumulation of either unconjugated or conjugated bilirubin and could be related to inherited bilirubin disorders. Three grades of inherited unconjugated hyperbilirubinemia are recognised in humans. This spectrum of disorders is distinguished primarily on the basis of the plasma bilirubin level, the response to phenobarbital administration, and the presence or absence of bilirubin glucoronides in bile. The enzyme responsible for the conjugation of bilirubin is the bilirubin uridine-diphosphate-glucuronosyltransferase (UGT). Mutations in the gene encoding bilirubin-UGT (UGT1A1), lead to complete or partial inactivation of the enzyme causing the rare autosomal recessively inherited conditions, Crigler-Najjar syndrome type 1 (CN-1) and type 2 (CN-2). Gilbert syndrome (GS) is due to an insertional mutation at homozygous state of the TATAA element (seven TA repeats) of UGT1A1 producing a reduced level of expression of the gene. The association of GS with haemolytic anemias, e.g., Hereditary Spherocytosis (HS) or Congenital Dyserythropoietic Anemia type 2 (CDA 2), increase the hyperbilirubinemia level and the risk of cholelithiasis. Forms of chronic conjugated hyperbilirubinemia are Dubin-Johnson syndrome, Rotor syndrome, Alagille syndrome or arteriohepatic dysplasia, Wilson disease or hepatolenticular degeneration. Liver or liver cell transplantation is the therapy in some cases.     

胆红素-尿苷二磷酸葡萄糖醛酸基转移酶G71R基因型对广西地区新生儿黄疸程度的影响

目的 探讨胆红素-尿苷二磷酸葡萄糖醛酸基转移酶1A1(UGT 1A1)基因突变对广西新生儿黄疸的影响.方法 收集73例高胆红素血症新生儿及31例健康新生儿外周血,应用突变特异性扩增系统(amplification refractory mutation system,ARMS)法及直接测序法对所有新生儿行UGT1A1基因G71R突变检测,分析胆红素脑病发生率,胆红素峰值及总胆红素(total serum bilirubin,TSB)>20 mg/dl的机会比.结果 (1)本研究人群G71R等位基因频率为0.1915,病例组为0.2329,健康对照组为0.097,病例组的G71R等位基因频率显著高于健康对照组(P<0.05).(2)G71R纯合子的胆红素脑病发病率及72 h的TSB浓度(28.57%,23.12±4.58 mg/dl)均高于野生型组(0%,17.68±2.69 mg/dl),差异有统计学意义(P<0.001).(3)G71R纯合子组中5例的TSB>20 mg/dl,G71R纯合子TSB>20 mg/dl的机会比(odds ratio,OR)为7.955,总体机会比95%可信区间(confidence interval,CI)为(1.349,46.899).结论 G71R突变与本地新生儿黄疸的发病存在相关性.G71R纯合子的胆红素脑病发病率及生后72 h的TSB较对照组及野生型增高.G71R纯合子发生TSB>20 mg/dl的危险性是野生型的7.955倍.     

Neonatal hyperbilirubinemia and the bilirubin uridine diphosphate-glucuronosyltransferase gene: The common −3263T > G mutation of phenobarbital response enhancer module is not associated with the neonatal hyperbilirubinemia in Japanese

BACKGROUND: Neonatal hyperbilirubinemia is frequent and severe in Japanese newborns. Previously, it has been reported that half of the Japanese neonates with severe hyperbilirubinemia carried the 211G > A (p.G71R) mutation of the bilirubin uridine diphosphate-glucuronosyltransferase (UGT1A1) gene causing Gilbert syndrome. Recently, it was reported that the -3263T > G mutation in the phenobarbital response enhancer module in UGT1A1 was associated with the majority of cases of Gilbert syndrome. The gene frequency of the -3263T > G mutation was determined and the relation with neonatal hyperbilirubinemia in Japanese was studied. METHODS: UGT1A1 in 119 neonates born at Yamagata University Hospital, Yamagata, Japan, and 26 subjects who had undergone phototherapy due to severe hyperbilirubinemia at four other hospitals were studied. The gene frequency of -3263T > G mutation in Japanese, Korean, Chinese and German healthy adult controls was also determined. Hyperbilirubinemia was assessed with a Jaundice Meter and UGT1A1 was analyzed by sequence determination or restriction enzyme method. RESULTS: The gene frequency of the -3263T > G mutation was 0.26 in Japanese subjects and was similar to the prevalence in Korean, Chinese and German populations. However, there was no significant increase in the gene frequency of the mutation in the neonates who required phototherapy for hyperbilirubinemia compared to that in the neonates without severe hyperbilirubinemia. In addition, neonates with or without the mutation did not show a significant change in the level of bilirubin and the mutation also did not show a synergic effect with the 211G > A mutation on the level of bilirubin. CONCLUSION: The -3263T > G mutation is not likely to be associated with the neonatal hyperbilirubinemia in Japanese.     

Relationship between bilirubin UDP-glucuronosyl transferase 1A1 gene and neonatal hyperbilirubinemia

The variation rate within the coding region of UDP-glucuronosyl transferase 1A1 (UGT1A1) gene in Taiwan Chinese was found to be 29.3%. This study sought to determine whether that high variation rate of UGT1A1 gene is a risk factor for neonatal hyperbilirubinemia. The study subjects consisted of 123 newborn infants suffering from unconjugated hyperbilirubinemia who had no known risk factors for hyperbilirubinemia and 218 healthy control neonates. The promoter area, exons 1 to 4, coding region of exon 5, and the flanking intronic regions in UGT1A1 gene were determined by the PCR in all subjects. Wild UGT1A1 gene, variation in the promoter, variation at nucleotide 211, variation at nucleotide 1091, and compound heterozygous variation of UGT1A1 gene were found. The percentage of neonates with wild UGT1A1 gene and the percentage of neonates with variation at nucleotide 211 were significantly different between the study subjects and controls. The percentages with bilirubin >or=342 micro M (20.0 mg/dL) and with persistent hyperbilirubinemia in the subjects carrying homozygous variation at nucleotide 211 (Gly71Arg) were significantly higher than the neonates carrying wild type or other genotypes. In conclusion, this study has demonstrated that variation at nucleotide 211 of the UGT1A1 gene is a risk factor for the development of neonatal hyperbilirubinemia. Pediatricians should closely follow hyperbilirubinemic newborn infants who carry homozygous 211 G to A variation in UGT1A1 gene.     

Neonatal hyperbilirubinemia and Gly71Arg mutation of UGT1A1 gene: a Chinese case-control study followed by systematic review of existing evidence

Aim: To determine whether the UDP‐glucuronosyltransferase 1A1 gene (UGT1A1) Gly71Arg (211G>A) mutation is associated with neonatal hyperbilirubinemia. Methods: The study consisted of two parts. The case–control study included 112 hyperbilirubinemic infants and 105 control subjects from the Fifth People’s Hospital of Shenzhen. Polymerase chain reaction, restriction fragment length polymorphisms and agarose gel electrophoresis techniques were used to detect the UGT1A1 211G>A mutation. Meta‐analyses was performed to assess the association between neonatal hyperbilirubinemia and UGT1A1 211G>A. Results: Our case–control study revealed that the likelihood of developing neonatal hyperbilirubinemia was 2.65 times higher in the infants with the A allele in the UGT1A1 211G>A than in the infants with the G allele (95% CI, 1.60–4.39). Meta‐analyses (including data from our study) revealed that UGT1A1 211G>A is associated with an increased risk of neonatal hyperbilirubinemia [ odds ratio (OR), 2.37; 95% CI, 2.05–2.74]. In the subgroup analyses based on ethnicity, significantly elevated risks were found in Asian populations (OR, 2.45; 95% CI, 2.10–2.84), but no significant associations were present in Caucasian populations (OR, 1.54; 95% CI, 0.87–2.75). Conclusion: The UGT1A1 211G>A mutation is associated with neonatal hyperbilirubinemia in Asians, but not in Caucasians.     

Homozygous variant of UGT1A1 gene mutation and severe neonatal hyperbilirubinemia

Background: The aim of the present study was to compare, in a case–control study, the prevalence of nucleotide 211 guanine to adenine (G→A) mutation of uridine diphosphoglucuronosyl transferase (UGT1A1) gene in Malaysian Chinese newborns with and without severe hyperbilirubinemia (total serum bilirubin >250 µmol/L during first 48 h of life or ≥300 µmol/L thereafter), and to determine whether this mutation was a significant risk factor associated with severe hyperbilirubinemia. Methods: Seventy‐four term infants of Chinese descent admitted with severe hyperbilirubinemia were recruited. Infants without severe hyperbilirubinemia (n = 125) were randomly selected from among healthy Chinese term infants. UGT1A1 nucleotide 211 polymorphism was assayed using the Taqman single nucleotide polymorphism genotyping method. Using gestational age, types of feeds, G6PD mutation, G6PD enzyme levels, and UGT1A1 gene mutation status as independent variables, logistic regression analysis was carried out to determine the significant risk factors associated with severe hyperbilirubinemia. Results: UGT1A1 gene mutation was significantly more common among hyperbilirubinemic infants (39.2%) than controls (25.6%; P = 0.04). Gestational age (adjusted odds ratio [OR], 0.7; 95% confidence intervals [CI]: 0.5–0.9; P = 0.01), G6PD mutation (adjusted OR, 7.2; 95%CI: 2.7–19.0; P < 0.0001), exclusive breast‐feeding (adjusted OR, 11.7; 95%CI: 2.7–49.9; P = 0.001), and homozygous variant of UGT1A1 gene mutation (adjusted OR, 32.2; 95%CI: 3.8–273.2; P = 0.001) were significant risk factors. Heterozygous variant of UGT1A1 gene mutation, actual levels of G6PD enzyme, and mixed feeding were not. Conclusion: Homozygous variant of nucleotide 211 G→A mutation of UGT1A1 gene is a significant risk factor associated with severe hyperbilirubinemia among Malaysian Chinese newborns.     

Gilbert's syndrome is a contributory factor in prolonged unconjugated hyperbilirubinemia of the newborn

OBJECTIVE: Prolonged neonatal jaundice, beyond day 14 of life, is very common and of concern to the clinician. The aim of this study was to investigate whether a genetic mutation in the bilirubin UGT1A1 gene, which has been associated with Gilbert's syndrome in adults, is a contributory factor in prolonged neonatal jaundice. STUDY DESIGN: Blood was collected from 85 term newborns with unexplained hyperbilirubinemia, and DNA was prepared. The neonates were divided into 6 groups depending on whether they were breast-fed or bottle-fed and whether they had acute, prolonged, or very prolonged jaundice. UGT1A1 TATA promoter genotyping (DNA test for Gilbert's syndrome) was performed on all samples, and analysis of the entire UGT1A1 coding sequence was performed in a representative sample (11 of 26) of very prolonged cases. RESULTS: In addition to the known common UGT1A1 TATA alleles (TA6 and TA7), a novel TATA allele (TA5) in a neonate with very prolonged jaundice was identified. Statistical analysis of the TATA genotype distributions within the group of breast-fed neonates revealed significant differences among the acute, prolonged, and very prolonged subgroups (.05 > P >.01): the incidence of familial hyperbilirubinemia genotypes (7/7 and 5/7) is 5 times greater in very prolonged cases (31%) relative to acute cases (6%). Neonates with prolonged jaundice from family pedigrees were observed to demonstrate the Gilbert's phenotype as children or young adults. CONCLUSIONS: A genetic predisposition to develop prolonged neonatal hyperbilirubinemia in breast-fed infants is associated with TATA box polymorphism of the UGT1A1 gene and will be recognized as Gilbert's syndrome in adulthood.     

反复皮肤、巩膜黄染2年

患儿,女,2岁,反复皮肤、巩膜黄染2年,无其他症状及体征,应用苯巴比妥类药物黄疸可缓解。实验室检查间接胆红素多次升高,转氨酶正常,肝脏影像学正常,无溶血证据。患儿尿苷二磷酸葡萄糖醛酸转移酶(UGT1A1)基因分析提示:存在已报道的GS致病突变,c.211GA(G71R)、c.1456TG(Y486D)双重纯合突变;父母均为G71R、Y486D双重杂合携带者,无黄疸症状。确诊为Gilbert综合征(GS)。该病较少见。高未结合胆红素血症不能用常见肝损害及溶血解释时,建议调查家族史,尽早完善基因分析,以发现某些先天性胆红素代谢障碍性疾病。     

Frequencies of A(TA)7TAA, G71R, and G493R mutations of the UGT1A1 gene in the Malaysian population

BACKGROUND: Gilbert syndrome is caused by defects in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene. These mutations differ among different populations and many of them have been found to be genetic risk factors for the development of neonatal jaundice. OBJECTIVES: The objective was to determine the frequencies of the following mutations in the UGT1A1 gene: A(TA)7TAA (the most common cause of Gilbert syndrome in Caucasians), G71R (more common in the Japanese and Taiwanese population), and G493R (described in a homozygous Malay woman with Crigler-Najjar syndrome type 2) in a group of Malaysian babies with hyperbilirubinemia and a group of normal controls. METHODS: The GeneScan fragment analysis was used to detect the A(TA)7TAA variant. Mutation screening of both G71R and G493R was performed using denaturing high performance liquid chromatography. RESULTS: Fourteen out of fifty-five neonates with hyperbilirubinemia (25%) carried the A(TA)7TAA mutation (10 heterozygous, 4 homozygous). Seven out of fifty controls (14%) carried this mutation (6 heterozygous, 1 homozygous). The allelic frequencies for hyperbilirubinemia and control patients were 16 and 8%, respectively (p=0.20). Heterozygosity for the G71R mutation was almost equal among both groups (5.5% for hyperbilirubinemia patients and 6.0% for controls; p=0.61). One subject (1.8%) in the hyperbilirubinemia group and none of the controls were heterozygous for the G493R mutation (p=0.476). CONCLUSIONS: The A(TA)7TAA seems more common than the G71R and G493R mutations in the Malaysian population.     

Eponym

Gilbert syndrome is a common autosomal dominant hereditary condition with incomplete penetrance and characterized by intermittent unconjugated hyperbilirubinemia in the absence of hepatocellular disease or hemolysis. In patients with Gilbert syndrome, uridine diphosphate–glucuronyl transferase activity is reduced to 30% of the normal, resulting in indirect hyperbilirubinemia. In its typical form, hyperbilirubinemia is first noticed as intermittent mild jaundice in adolescence. However, Gilbert syndrome in combination with other prevailing conditions such as breast feeding, G-6-PD deficiency, thalassemia, spherocytosis, or cystic fibrosis may potentiate severe hyperbilirubinemia and/or cholelithiasis. It may also reduce plasma oxidation, and it may also affect drug metabolism. Although in general the diagnosis of the syndrome is one of exclusion, molecular genetic tests can now be performed when there is a diagnostic problem. The most common genotype of Gilbert syndrome is the homozygous polymorphism A(TA)7TAA in the promoter of the gene for UDP-glucuronosyltransferase 1A1 (UGT1A1), which is a TA insertion into the promoter designated UGT1A1*28. No specific management is necessary as Gilbert syndrome is a benign condition. Conclusion: Gilbert genotype should be kept in the clinician’s mind, at least as a contributor factor, in cases with unexplained indirect hyperbilirubinemia.     

Persistent jaundice in an infant with homozygous beta thalassemia due to co‐inherited Crigler–Najjar syndrome

Clinically apparent jaundice is unusual in patients with β‐thalassemia major. Co‐inheritance of Gilbert syndrome has been reported to cause hyperbilirubinemia in these subjects. Crigler–Najjar syndrome is another rare disorder of bilirubin metabolism caused by mutation in the gene coding the enzyme UGT1A1. We report a patient of β‐thalassemia major who presented with persistent jaundice due to co‐inherited Crigler–Najjar syndrome type 2 secondary to a novel mutation in UGT1A1 gene [homozygous base substitution at position 362 (GGT>AGT) in exon 3]. Pediatr Blood Cancer 2010;54:627–628. © 2009 Wiley‐Liss, Inc.     

A new case of (TA)8 allele in the UGT1A1 gene promoter in a Caucasian girl with Gilbert syndrome

The authors describe a 5-year-old Caucasian girl, referred to their hospital for evaluation of an unconjugated hyperbilirubinemia (57.9 μmol/L) detected from blood analysis during an episode of fever. The molecular analysis of the TATA-box region of the UGT1A1 gene revealed that the patient was a compound heterozygote for two insertions, one TA and the other TATA [(TA)₇/(TA)₈]. This is the first case of (TA)8 allele found in a Portuguese Caucasian patient and the third found in the literature.