BACKGROUND Benign recurrent intrahepatic cholestasis is a genetic disorder with recurrent cholestatic jaundice due to ATP8B1 and ABCB11 gene mutations encoding for hepato-canalicular transporters.Herein,we firstly pro...BACKGROUND Benign recurrent intrahepatic cholestasis is a genetic disorder with recurrent cholestatic jaundice due to ATP8B1 and ABCB11 gene mutations encoding for hepato-canalicular transporters.Herein,we firstly provide the evidence that a nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygous form is involved in BRIC pathogenesis.CASE SUMMARY A 29-year-old male showed severe jaundice and laboratory tests consistent with intrahepatic cholestasis despite normal gamma-glutamyltranspeptidase.Acute and chronic liver diseases with viral,metabolic and autoimmune etiology were excluded.Normal intra/extra-hepatic bile ducts were demonstrated by magnetic resonance.Liver biopsy showed:Cholestasis in the centrilobular and intermediate zones with bile plugs and intra-hepatocyte pigment,Kupffer’s cell activation/hyperplasia and preserved biliary ducts.Being satisfied benign recurrent intrahepatic cholestasis diagnostic criteria,ATP8B1 and ABCB11 gene analysis was performed.Surprisingly,we found a novel nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygosis.The variant was confirmed by Sanger sequencing following a standard protocol and tested for familial segregation,showing a maternal inheritance.Immunohistochemistry confirmed a significant reduction of mutated gene related protein(familial intrahepatic cholestasis 1).The patient was treated with ursodeoxycholic acid 15 mg/kg per day and colestyramine 8 g daily with total bilirubin decrease and normalization at the 6th and 12th mo.CONCLUSION A genetic abnormality,different from those already known,could be involved in familial intrahepatic cholestatic disorders and/or pro-cholestatic genetic predisposition,thus encouraging further mutation detection in this field.展开更多
对西藏16个牦牛类群共367头个体的mt DNA ATP8（Adenosine Triphosphate 8）基因进行克隆及序列分析。结果表明,西藏牦牛mt DNA ATP8基因全长201-203 bp,T、C、A和G 4种核苷酸的平均比例分别为29.3%、23.0%、41.8%和6.0%,A＋T含量明显高...对西藏16个牦牛类群共367头个体的mt DNA ATP8（Adenosine Triphosphate 8）基因进行克隆及序列分析。结果表明,西藏牦牛mt DNA ATP8基因全长201-203 bp,T、C、A和G 4种核苷酸的平均比例分别为29.3%、23.0%、41.8%和6.0%,A＋T含量明显高于G＋C,表现出一定的碱基偏倚性;在367头牦牛中,共检测到19个变异位点,其中单一信息位点15个,简约信息位点4个,存在转换和插入2种变异类型,碱基替换中存在转换73次,以A/G、T/C为主,占98.63%;在插入变异类型中以A碱基插入为主;367头牦牛共捡出20种单倍型,单倍型多样性和核苷酸多样性指数分别为0.332和0.001 89,说明西藏牦牛具有较贫乏的遗传多样性;聚类分析显示,西藏牦牛可分为2类,其中桑日牦牛、类乌齐牦牛和桑日牦牛为1类,其余牦牛类群为另1类。20种单倍型可以分为2个聚类簇（I和Ⅱ）,其中聚类簇I包含17种单倍型,占全部单倍型数的77.27%,包含了本次研究中的所有西藏牦牛类群;聚类簇Ⅱ中有3种单倍型,囊括了除错那、嘉黎、康布和帕里类群外的12个类群,显示西藏牦牛存在2个母系起源。展开更多
Recent reports in patients with PFIC1 have indicated that a gene defect in ATP8B1 could cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. This study aimed to:(1) define...Recent reports in patients with PFIC1 have indicated that a gene defect in ATP8B1 could cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. This study aimed to:(1) define ATP8B1 expression in human hepatobiliary cell types, and (2) determine whether ATP8B1 defect affects gene expressions related to bile secretion in these cells. ATP8B1 expression was detected by RT-PCR in hepatocytes and cholangiocytes isolated from normal human liver and gallbladder. ATP8B1 mRNA levels were 20-and 200-fold higher in bile duct and gallbladder epithelial cells, respectively, than in hepatocytes. RT-PCR analyses of the liver from two patients with PFIC1, one with PFIC2, one with biliary atresia, showed that, compared to normal liver, hepatic expressions of FXR, SHP, CYP7A1, ASBT were decreased at least by 90%in all cholestatic disorders. In contrast, NTCP transcripts were less decreased(by ≤30%vs. 97%) in PFIC1 as compared with other cholestatic disorders, while BSEP transcripts, in agreement with BSEP immunohistochemical signals, were normal or less decreased(by 50%vs. 97%). CFTR hepatic expression was decreased(by 80%), exclusively in PFIC1, while bile duct mass was not reduced, as ascertained by cytokeratin-19 immunolabeling. In Mz-ChA-2 human biliary epithelial cells, a significant decrease in CFTR expression was associated with ATP8B1 invalidation by siRNA. In conclusion, cholangiocytes are a major site of ATP8B1 hepatobiliary expression. A defect of ATP8B1 along with CFTR downregulation can impair the contribution of these cells to bile secretion, and potentially explain the extrahepatic cystic fibrosis-like manifestations that occur in PFIC1.展开更多
Background: Intrahepatic cholestasis of pregnancy (ICP) affects approximately 0.7%of pregnancies in the UK and is associated with prematurity, fetal distress, and intrauterine death. Homozygous mutations in the ATP8B1...Background: Intrahepatic cholestasis of pregnancy (ICP) affects approximately 0.7%of pregnancies in the UK and is associated with prematurity, fetal distress, and intrauterine death. Homozygous mutations in the ATP8B1 gene cause cholestasis with a normal serum gamma-glutamyl transpeptidase (γ-GT), and have been reported in two forms of cholestasis: progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis (BRIC). Aims: To establish whether mutations in ATP8B1 are associated with ICP in British cases. Patients: Sixteen well phenotyped women with ICP without raised γ-GT were selected for sequence analysis. Subsequently, 182 patients and 120 controls were examined for the presence of the variants detected. Methods: All coding exons were sequenced in 16 cases. Eight ICP cases, including two women carrying a mutation, were investigated using in vivo hepatic 31P magnetic resonance spectroscopy (MRS). Results: Two heterozygous ATP8B1 transitions (208G >A and 2599C >T) that resulted in amino acid substitutions were identified; 208G >A was identified in three cases. MRS revealed an increased phosphodiester signal (Mann-Whitney U test, p = 0.03) and a decreased phosphomonoester/phosphodiester ratio (p = 0.04) in ICP cases compared with controls. Conclusions: We were able to demonstrate ATP8B1 mutations in ICP. MRS studies suggest that susceptibility to ICP is associated with a relative rise in biliary phospholipid. These data also suggest that MRS may be used for non-invasive assessment of the liver and biliary constituents in cholestasis.展开更多
BACKGROUND Genetic disorders affecting hepatobiliary transporters can be triggered by various factors,resulting in marked cholestasis.CASE SUMMARY We report two patients who experienced a severe episode of intrahepati...BACKGROUND Genetic disorders affecting hepatobiliary transporters can be triggered by various factors,resulting in marked cholestasis.CASE SUMMARY We report two patients who experienced a severe episode of intrahepatic cholestasis triggered by an acute hepatitis E virus infection.Following an extensive clinical examination that ruled out common causes of cholestatic liver damage,we conducted next-generation sequencing to determine the genetic profiles of the patients.The analysis revealed several known and unknown variants in genes associated with hepatobiliary transporters and bile salt regulation,including ATP8B1,ABCB11,ABCB4,MYO5B,and FXR.For a comprehensive understanding of the pathophysiology,we performed ClinVar analysis and utilized PolyPhen for bioinformatic prediction of functional impact.Both patients exhibited rapid symptom improvement and a decrease in hyperbilirubinemia when treated with either rifampicin or bezafibrate.CONCLUSION Our findings introduce hepatitis E viral infection as a novel trigger for intrahepatic cholestasis,and we categorize the significance of the various genetic variants based on the current state of research.展开更多
文摘BACKGROUND Benign recurrent intrahepatic cholestasis is a genetic disorder with recurrent cholestatic jaundice due to ATP8B1 and ABCB11 gene mutations encoding for hepato-canalicular transporters.Herein,we firstly provide the evidence that a nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygous form is involved in BRIC pathogenesis.CASE SUMMARY A 29-year-old male showed severe jaundice and laboratory tests consistent with intrahepatic cholestasis despite normal gamma-glutamyltranspeptidase.Acute and chronic liver diseases with viral,metabolic and autoimmune etiology were excluded.Normal intra/extra-hepatic bile ducts were demonstrated by magnetic resonance.Liver biopsy showed:Cholestasis in the centrilobular and intermediate zones with bile plugs and intra-hepatocyte pigment,Kupffer’s cell activation/hyperplasia and preserved biliary ducts.Being satisfied benign recurrent intrahepatic cholestasis diagnostic criteria,ATP8B1 and ABCB11 gene analysis was performed.Surprisingly,we found a novel nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygosis.The variant was confirmed by Sanger sequencing following a standard protocol and tested for familial segregation,showing a maternal inheritance.Immunohistochemistry confirmed a significant reduction of mutated gene related protein(familial intrahepatic cholestasis 1).The patient was treated with ursodeoxycholic acid 15 mg/kg per day and colestyramine 8 g daily with total bilirubin decrease and normalization at the 6th and 12th mo.CONCLUSION A genetic abnormality,different from those already known,could be involved in familial intrahepatic cholestatic disorders and/or pro-cholestatic genetic predisposition,thus encouraging further mutation detection in this field.
文摘对西藏16个牦牛类群共367头个体的mt DNA ATP8（Adenosine Triphosphate 8）基因进行克隆及序列分析。结果表明,西藏牦牛mt DNA ATP8基因全长201-203 bp,T、C、A和G 4种核苷酸的平均比例分别为29.3%、23.0%、41.8%和6.0%,A＋T含量明显高于G＋C,表现出一定的碱基偏倚性;在367头牦牛中,共检测到19个变异位点,其中单一信息位点15个,简约信息位点4个,存在转换和插入2种变异类型,碱基替换中存在转换73次,以A/G、T/C为主,占98.63%;在插入变异类型中以A碱基插入为主;367头牦牛共捡出20种单倍型,单倍型多样性和核苷酸多样性指数分别为0.332和0.001 89,说明西藏牦牛具有较贫乏的遗传多样性;聚类分析显示,西藏牦牛可分为2类,其中桑日牦牛、类乌齐牦牛和桑日牦牛为1类,其余牦牛类群为另1类。20种单倍型可以分为2个聚类簇（I和Ⅱ）,其中聚类簇I包含17种单倍型,占全部单倍型数的77.27%,包含了本次研究中的所有西藏牦牛类群;聚类簇Ⅱ中有3种单倍型,囊括了除错那、嘉黎、康布和帕里类群外的12个类群,显示西藏牦牛存在2个母系起源。
文摘Recent reports in patients with PFIC1 have indicated that a gene defect in ATP8B1 could cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. This study aimed to:(1) define ATP8B1 expression in human hepatobiliary cell types, and (2) determine whether ATP8B1 defect affects gene expressions related to bile secretion in these cells. ATP8B1 expression was detected by RT-PCR in hepatocytes and cholangiocytes isolated from normal human liver and gallbladder. ATP8B1 mRNA levels were 20-and 200-fold higher in bile duct and gallbladder epithelial cells, respectively, than in hepatocytes. RT-PCR analyses of the liver from two patients with PFIC1, one with PFIC2, one with biliary atresia, showed that, compared to normal liver, hepatic expressions of FXR, SHP, CYP7A1, ASBT were decreased at least by 90%in all cholestatic disorders. In contrast, NTCP transcripts were less decreased(by ≤30%vs. 97%) in PFIC1 as compared with other cholestatic disorders, while BSEP transcripts, in agreement with BSEP immunohistochemical signals, were normal or less decreased(by 50%vs. 97%). CFTR hepatic expression was decreased(by 80%), exclusively in PFIC1, while bile duct mass was not reduced, as ascertained by cytokeratin-19 immunolabeling. In Mz-ChA-2 human biliary epithelial cells, a significant decrease in CFTR expression was associated with ATP8B1 invalidation by siRNA. In conclusion, cholangiocytes are a major site of ATP8B1 hepatobiliary expression. A defect of ATP8B1 along with CFTR downregulation can impair the contribution of these cells to bile secretion, and potentially explain the extrahepatic cystic fibrosis-like manifestations that occur in PFIC1.
文摘Background: Intrahepatic cholestasis of pregnancy (ICP) affects approximately 0.7%of pregnancies in the UK and is associated with prematurity, fetal distress, and intrauterine death. Homozygous mutations in the ATP8B1 gene cause cholestasis with a normal serum gamma-glutamyl transpeptidase (γ-GT), and have been reported in two forms of cholestasis: progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis (BRIC). Aims: To establish whether mutations in ATP8B1 are associated with ICP in British cases. Patients: Sixteen well phenotyped women with ICP without raised γ-GT were selected for sequence analysis. Subsequently, 182 patients and 120 controls were examined for the presence of the variants detected. Methods: All coding exons were sequenced in 16 cases. Eight ICP cases, including two women carrying a mutation, were investigated using in vivo hepatic 31P magnetic resonance spectroscopy (MRS). Results: Two heterozygous ATP8B1 transitions (208G >A and 2599C >T) that resulted in amino acid substitutions were identified; 208G >A was identified in three cases. MRS revealed an increased phosphodiester signal (Mann-Whitney U test, p = 0.03) and a decreased phosphomonoester/phosphodiester ratio (p = 0.04) in ICP cases compared with controls. Conclusions: We were able to demonstrate ATP8B1 mutations in ICP. MRS studies suggest that susceptibility to ICP is associated with a relative rise in biliary phospholipid. These data also suggest that MRS may be used for non-invasive assessment of the liver and biliary constituents in cholestasis.
文摘BACKGROUND Genetic disorders affecting hepatobiliary transporters can be triggered by various factors,resulting in marked cholestasis.CASE SUMMARY We report two patients who experienced a severe episode of intrahepatic cholestasis triggered by an acute hepatitis E virus infection.Following an extensive clinical examination that ruled out common causes of cholestatic liver damage,we conducted next-generation sequencing to determine the genetic profiles of the patients.The analysis revealed several known and unknown variants in genes associated with hepatobiliary transporters and bile salt regulation,including ATP8B1,ABCB11,ABCB4,MYO5B,and FXR.For a comprehensive understanding of the pathophysiology,we performed ClinVar analysis and utilized PolyPhen for bioinformatic prediction of functional impact.Both patients exhibited rapid symptom improvement and a decrease in hyperbilirubinemia when treated with either rifampicin or bezafibrate.CONCLUSION Our findings introduce hepatitis E viral infection as a novel trigger for intrahepatic cholestasis,and we categorize the significance of the various genetic variants based on the current state of research.
