Progressive Familial Intrahepatic Cholestasis-2 Mimicking Non-accidental Injury.

Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of disorders characterized by defective secretion of bile acids or transport defects resulting in progressive cholestasis. These disorders usually present during infancy or childhood and are associated with progressive liver disease. PFIC is estimated to affect 1 in 50,000-100,000 births, with PFIC-2 representing half of PFIC cases. PFIC-2 presents with hepatosplenomegaly, jaundice, pruritus, fat-soluble vitamin deficiencies, and growth failure. Laboratory findings include low/normal gamma glutamyl transpeptidase levels and elevated bilirubin, transaminases, and alpha-fetoprotein levels. In this report, we present a case of PFIC-2 presenting with severe coagulopathy, bruising, subcutaneous hematomas, and acute-onset anemia.

Sphincter of Oddi Dysfunction Induces Gallstone by Inhibiting the Expression of ABCB11 via PKC-α.

The abnormal increase of Oddi sphincter pressure and total bile duct pressure may play an important role in the formation of cholesterol stones, but the specific molecular mechanism is still unclear. This study aims to investigate it through in vitro and in vivo experiments. A mouse model of Oddi sphincter dysfunction was constructed by stone-inducing diet. We compared the two groups with PKC-α inhibitor GÖ6976 and PKC-α agonist thymeleatoxin. Oddi sphincter pressure and total bile duct pressure were measured. Biochemical analysis of total cholesterol, bile acid and bilirubin was then conducted. The histopathologic changes of bile duct were observed by HE staining and the ultrastructure of liver cells and surrounding tissues was observed by transmission electron microscopy. Through the above experiments, we found that the change of PKC-α expression may affect the formation process of gallstones. The relationship between PKC-α and ABCB11 was further verified by in vitro and in vivo experiments. Our results suggest that ABCB11 and PKC-α are co-expressed in the tubule membrane of hepatocytes and interact with each other in hepatocytes. The high cholesterol diet further enhances the activation of PKC-α and thus reduces the expression of ABCB11. The formation of cholesterol stones is associated with the down-regulation of ABCB11 expression in the tubule membrane of hepatocytes due to kinase signaling. This is the first study to demonstrate that sphincter of Oddi dysfunction induces gallstones through PKC-α inhibition of ABCB11 expression.

Clinicopathologic Features, Genetics, Treatment, and Long-Term Outcomes in Japanese Children and Young Adults with Benign Recurrent Intrahepatic Cholestasis: A Multicenter Study.

BACKGROUND: Few reports of benign recurrent intrahepatic cholestasis (BRIC) have focused on East Asian patients. We describe the clinicopathologic features, genetics, treatment, and outcomes in Japanese BRIC patients. METHODS: We recruited patients with BRIC type 1 (BRIC-1) or 2 (BRIC-2) treated at four pediatric centers and one adult center between April 2007 and March 2022. Demographics, clinical course, laboratory results, molecular genetic findings concerning ATP8B1 and ABCB11 genes, histopathology, and treatment response were examined retrospectively. RESULTS: Seven Japanese patients with BRIC were enrolled (four male, three female; four BRIC-1 and three BRIC-2). The median age at onset for BRIC-1 was 12 years; for BRIC-2, it was 1 month. Intermittent cholestatic attacks numbered from one to eight during the 11 years of median follow-up. Six patients received a mainstream education; only one patient attended special education. None developed cirrhosis. Three with BRIC-1 showed compound heterozygosity for a variant ATP8B1 gene, while one was heterozygous; two BRIC-2 patients showed compound heterozygosity in ABCB11 and one was heterozygous. Liver biopsy specimens obtained during cholestatic attacks showed fibrosis varying from none to moderate; inflammation was absent or mild. Rifampicin administered to three patients for cholestatic attacks was effective in all, as was cholestyramine in two of three. CONCLUSIONS: To our knowledge, this is the first East Asian multicenter study of BRIC patients. Onset age and number of cholestatic attacks varied. Rifampicin and cholestyramine were effective against attacks. No patient developed cirrhosis; most had normal growth and development. The long-term outcomes were satisfactory.

Schizophrenia-associated somatic copy-number variants from 12,834 cases reveal recurrent NRXN1 and ABCB11 disruptions.

While germline copy-number variants (CNVs) contribute to schizophrenia (SCZ) risk, the contribution of somatic CNVs (sCNVs)-present in some but not all cells-remains unknown. We identified sCNVs using blood-derived genotype arrays from 12,834 SCZ cases and 11,648 controls, filtering sCNVs at loci recurrently mutated in clonal blood disorders. Likely early-developmental sCNVs were more common in cases (0.91%) than controls (0.51%, p = 2.68e-4), with recurrent somatic deletions of exons 1-5 of the NRXN1 gene in five SCZ cases. Hi-C maps revealed ectopic, allele-specific loops forming between a potential cryptic promoter and non-coding cis-regulatory elements upon 5' deletions in NRXN1. We also observed recurrent intragenic deletions of ABCB11, encoding a transporter implicated in anti-psychotic response, in five treatment-resistant SCZ cases and showed that ABCB11 is specifically enriched in neurons forming mesocortical and mesolimbic dopaminergic projections. Our results indicate potential roles of sCNVs in SCZ risk.

ABCB11 accumulated in immature tertiary lymphoid structures participates in xenobiotic metabolic process and predicts resistance to PD-1/PD-L1 inhibitors in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinomas (HNSCC) are at a high risk of recurrence and multimodal therapy have not significantly improved survival in recent decades. Although immune checkpoint inhibitors (ICIs) are effective in a small proportion of HNSCC patients, the majority do not respond. In this study, we for the first time revealed that xenobiotic metabolic process was significantly associated with resistance to programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors in HNSCC and found that ATP binding cassette subfamily B member 11 (ABCB11) accumulated in immature tertiary lymphoid structures (TLSs) predicted worse progression-free survival (PFS) and overall survival (OS) after PD-1/PD-L1 inhibitors therapy. Moreover, the expression of cytochrome P450 1A2 (CYP1A2), a cytochrome P450 (CYP) enzyme that participates in xenobiotic metabolic process, was significantly upregulated in CD45+ABCB11+ tumor-infiltrating lymphocytes (TILs) compared with CD45+ABCB11-TILs in HNSCC tissues. Whole slide scans of 110 HNSCC tissues with hematoxylin-eosin (HE) and multispectral immuno-fluorescent (mIF) staining revealed that ABCB11 had a high co-expression with CYP1A2 in immature TLSs, and colocalization of ABCB11 and CYP1A2 in immature TLs significantly associated with high infiltration of immunosuppressive T-regulatory (Treg). Our study revealed that ABCB11 accumulated in immature TLSs might upregulate CYP1A2 to mediate xenobiotic metabolic process, thus increase the immunosuppressive Treg infiltration, and induce resistance to PD-1/PD-L1 inhibitors in HNSCC.

Molecular and Clinical Links between Drug-Induced Cholestasis and Familial Intrahepatic Cholestasis.

Idiosyncratic Drug-Induced Liver Injury (iDILI) represents an actual health challenge, accounting for more than 40% of hepatitis cases in adults over 50 years and more than 50% of acute fulminant hepatic failure cases. In addition, approximately 30% of iDILI are cholestatic (drug-induced cholestasis (DIC)). The liver's metabolism and clearance of lipophilic drugs depend on their emission into the bile. Therefore, many medications cause cholestasis through their interaction with hepatic transporters. The main canalicular efflux transport proteins include: 1. the bile salt export pump (BSEP) protein (ABCB11); 2. the multidrug resistance protein-2 (MRP2, ABCC2) regulating the bile salts' independent flow by excretion of glutathione; 3. the multidrug resistance-1 protein (MDR1, ABCB1) that transports organic cations; 4. the multidrug resistance-3 protein (MDR3, ABCB4). Two of the most known proteins involved in bile acids' (BAs) metabolism and transport are BSEP and MDR3. BSEP inhibition by drugs leads to reduced BAs' secretion and their retention within hepatocytes, exiting in cholestasis, while mutations in the ABCB4 gene expose the biliary epithelium to the injurious detergent actions of BAs, thus increasing susceptibility to DIC. Herein, we review the leading molecular pathways behind the DIC, the links with the other clinical forms of familial intrahepatic cholestasis, and, finally, the main cholestasis-inducing drugs.

Genotype-phenotype relationships of truncating mutations, p.E297G and p.D482G in bile salt export pump deficiency.

Background & Aims: Bile salt export pump (BSEP) deficiency frequently necessitates liver transplantation in childhood. In contrast to two predicted protein truncating mutations (PPTMs), homozygous p.D482G or p.E297G mutations are associated with relatively mild phenotypes, responsive to surgical interruption of the enterohepatic circulation (siEHC). The phenotype of patients with a compound heterozygous genotype of one p.D482G or p.E297G mutation and one PPTM has remained unclear. We aimed to assess their genotype-phenotype relationship. Methods: From the NAPPED database, we selected patients with homozygous p.D482G or p.E297G mutations (BSEP1/1; n = 31), with one p.D482G or p.E297G, and one PPTM (BSEP1/3; n = 30), and with two PPTMs (BSEP3/3; n = 77). We compared clinical presentation, native liver survival (NLS), and the effect of siEHC on NLS. Results: The groups had a similar median age at presentation (0.7-1.3 years). Overall NLS at age 10 years was 21% in BSEP1/3 vs. 75% in BSEP1/1 and 23% in BSEP3/3 (p <0.001). Without siEHC, NLS in the BSEP1/3 group was similar to that in BSEP3/3, but considerably lower than in BSEP1/1 (at age 10 years: 38%, 30%, and 71%, respectively; p = 0.003). After siEHC, BSEP1/3 and BSEP3/3 were associated with similarly low NLS, while NLS was much higher in BSEP1/1 (10 years after siEHC, 27%, 14%, and 92%, respectively; p <0.001). Conclusions: Individuals with BSEP deficiency with one p.E297G or p.D482G mutation and one PPTM have a similarly severe disease course and low responsiveness to siEHC as those with two PPTMs. This identifies a considerable subgroup of patients who are unlikely to benefit from interruption of the enterohepatic circulation by either surgical or ileal bile acid transporter inhibitor treatment. Impact and implications: This manuscript defines the clinical features and prognosis of individuals with BSEP deficiency involving the combination of one relatively mild and one very severe BSEP deficiency mutation. Until now, it had always been assumed that the mild mutation would be enough to ensure a relatively good prognosis. However, our manuscript shows that the prognosis of these patients is just as poor as that of patients with two severe mutations. They do not respond to biliary diversion surgery and will likely not respond to the new IBAT (ileal bile acid transporter) inhibitors, which have recently been approved for use in BSEP deficiency.

Heterozygous mutations of ATP8B1, ABCB11 and ABCB4 cause mild forms of Progressive Familial Intrahepatic Cholestasis in a pediatric cohort / Mutaciones en heterocigosis en ATP8B1, ACB11 y ABCB4 como causa de formas leves de Colestasis Intrahepática Progresiva Familiar en una cohorte pediátrica

Introduction: Heterozygous defects in genes implicated in Progressive Familial Intrahepatic Cholestasis have been described in milder forms of cholestatic diseases. Our aim is to describe clinical, laboratory and imaging characteristics as well as treatment and outcome of a cohort of pediatric patients with heterozygous mutations in ATP8B1, ABCB11 or ABCB4. Patients and methods: We present a retrospective descriptive study including pediatric patients with at least one heterozygosis defect in ATP8B1, ABCB11 or ABCB4 diagnosed after a cholestatic episode. Clinical, diagnostic and outcome data were collected including gene analysis (panel of PFIC NextGeneDx®). Results: 7 patients showed a heterozygous mutation: 3 patients in ABCB4, 1 in ABCB11, 2 in ABCB4 and ABCB11 and 1 in ATP8B1. The median onset age was 5.5 years with a median time of follow-up of 6 years. The initial presentation was pruritus followed by asymptomatic hypertransaminasemia and persistent cholestasis. Two patients had family history of gallbladder stones and mild hepatitis. All showed elevated transaminases and bile acids, high gamma glutamyl-transferase (GGT) in 3 and conjugated bilirubin in 2 patients. Liver biopsy showed inflammatory infiltrate or mild fibrosis with normal immunohistochemistry. All patients were treated with ursodeoxycholic acid, two patients requiring the addition of resincholestyramine. During follow-up, 3 patients suffered limited relapses of pruritus. No disease progression was observed. Conclusion: Heterozygous mutations in genes coding proteins of the hepatocellular transport system can cause cholestatic diseases with great phenotypic variability. The presence of repeated episodes of hypertransaminasemia or cholestasis after a trigger should force us to rule out the presence of these heterozygous mutations in genes involved in CIFP.(AU)

Introducción: Se han descrito defectos en los genes implicados en las colestasis intrahepáticas familiares progresivas (CIFP) causantes de colestasis más leves. El objetivo es estudiar las manifestaciones clínicas, analíticas y de imagen así como la evolución y respuesta al tratamiento de los portadores en heterocigosis de mutaciones en ATP8B1, ABCB11 y ABCB4. Pacientes y métodos: Estudio descriptivo retrospectivo de pacientes con al menos una mutación en heterocigosis en los genes ATP8B1, ABCB11 o ABCB4 diagnosticados tras un episodio de colestasis. Se recogieron variables demográficas y datos clínicos, diagnósticos, incluyendo estudio genético (panel de CIFP NextGeneDx®), tratamiento y evolución. Resultados: 7 pacientes presentaron al menos una mutación en heterocigosis: 3 en ABCB4, 1 en ABCB11, 2 en ABCB4 y ABCB11 y 1 en ATP8B1. La edad media de inicio fue de 5.5 años con un tiempo medio de evolución de 6 años. La clínica inicial fue prurito seguida de hipertransaminasemia asintomática y colestasis persistente. Dos pacientes tenían antecedentes familiares de litiasis biliar y hepatitis leve. Todos mostraron transaminasas y ácidos biliares elevados, 3 gamma-glutamiltransferasa (GGT) y 2 bilirrubina directa. La biopsia hepática mostró infiltrado inflamatorio o fibrosis leve, inmunohistoquímica normal. Fueron tratados con ácido ursodeoxicólico añadiéndose colestiramina en 2. Durante el seguimiento 3 presentaron episodios autolimitados de prurito. No se observó progresión de la enfermedad. Conclusiones: Mutaciones en heterocigosis en los genes implicados en el sistema de transporte hepatocelular pueden ocasionar cuadros de colestasis con gran variabilidad fenotípica. Episodios repetidos de hipertransaminasemia o colestasis tras un desencadenante deben hacernos sospechar mutaciones en los genes implicados en las CIFP.(AU)

Rare Inherited Cholestatic Disorders and Molecular Links to Hepatocarcinogenesis.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer affecting adults and the second most common primary liver cancer affecting children. Recent years have seen a significant increase in our understanding of the molecular changes associated with HCC. However, HCC is a complex disease, and its molecular pathogenesis, which likely varies by aetiology, remains to be fully elucidated. Interestingly, some inherited cholestatic disorders that manifest in childhood are associated with early HCC development. This review will thus explore how three genes that are associated with liver disease in childhood (ABCB11, TJP2 and VPS33B) might play a role in the initiation and progression of HCC. Specifically, chronic bile-induced damage (caused by ABCB11 changes), disruption of intercellular junction formation (caused by TJP2 changes) and loss of normal apical-basal cell polarity (caused by VPS33B changes) will be discussed as possible mechanisms for HCC development.

Clinical and Genetic Risk Factors for Drug-Induced Liver Injury Associated with Anti-Tuberculosis Treatment-A Study from Patients of Portuguese Health Centers.

Drug-induced liver injury (DILI) is an unpredictable and feared side effect of antituberculosis treatment (AT). The present study aimed to identify clinical and genetic variables associated with susceptibility to AT-associated hepatotoxicity in patients with pulmonary tuberculosis treated with a standard protocol. Of 233 patients enrolled, 90% prospectively, 103 developed liver injury: 37 with mild and 66 with severe phenotype (DILI). All patients with mild hepatitis had a RUCAM score ≥4 and all patients with DILI had a RUCAM score ≥ 6. Eight clinical variables and variants in six candidate genes were assessed. A logistic multivariate regression analysis identified four risk factors for AT-DILI: age ≥ 55 years (OR:3.67; 95% CI:1.82−7.41; p < 0.001), concomitant medication with other hepatotoxic drugs (OR:2.54; 95% CI:1.23−5.26; p = 0.012), NAT2 slow acetylator status (OR:2.46; 95% CI:1.25−4.84; p = 0.009), and carriers of p.Val444Ala variant for ABCB11 gene (OR:2.06; 95%CI:1.02−4.17; p = 0.044). The statistical model explains 24.9% of the susceptibility to AT-DILI, with an 8.9 times difference between patients in the highest and in the lowest quartiles of risk scores. This study sustains the complex architecture of AT-DILI. Prospective studies should evaluate the benefit of NAT2 and ABCB11 genotyping in AT personalization, particularly in patients over 55 years.

A New Variant of an Old Itch: Novel Missense Variant in ABCB4 Presenting with Intractable Pruritus.

We report a novel homozygous missense variant in ABCB4 gene in a Yemeni child born to consanguineous parents, with a significant family history of liver disease-related deaths, resulting in a progressive familial intrahepatic cholestasis (PFIC) type 3 phenotype requiring liver transplantation for intractable pruritus.

Antisense oligonucleotides rescue an intronic splicing variant in the ABCB11 gene that causes progressive familial intrahepatic cholestasis type 2.

BACKGROUND: Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a rare disorder caused by variants in the ABCB11 gene encoding the bile salt export pump (BSEP). We investigated the molecular defect in a PFIC2 infant and rescued the splicing defect with antisense oligonucleotides (ASOs). METHODS: Whole-exome sequencing (WES) revealed compound heterozygous variants in the ABCB11 gene in a PFIC2 patient. Liver biopsy was immunostained for BSEP. The splicing effect of the candidate variants was investigated by minigene assay. ASOs were designed to rescue aberrant splicing. RESULTS: A Chinese girl of two nonconsanguineous healthy parents suffered from low glutamyl transpeptidase cholestasis and showed no response to the ursodeoxycholic acid. WES revealed that the patient was compound heterozygous for two novel variants in the ABCB11 gene: c.76+29T>G and c.390-2A>G. Liver immunohistochemistry showed the absence of BSEP. The variant c.76+29T>G was confirmed to retain 42 bp in the mature mRNA. The variant c.390-2A>G was confirmed to cause exon 6 skipping. We designed two ASOs and identified one of them that efficiently induced pseudoexon exclusion. CONCLUSION: We reported two novel variants of the ABCB11 gene, c.76+29T>G and c.390-2A>G, in a PFIC2 infant, thereby expanding the genotype of PFIC2. Our findings provide evidence for ASOs as a therapeutic approach for PFIC2 patients carrying intronic variants.

A study of exons 14, 15, and 24 of the ABCB11 gene in Egyptian children with normal GGT cholestasis.

BACKGROUND AND STUDY AIMS: Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a rare inherited disorder caused by mutation in the ATP-binding cassette subfamily B member 11 gene (ABCB11) that encodes the bile salt export pump (BSEP), which is the main transporter of bile acids from hepatocytes to the canalicular lumen. Defects in BSEP synthesis and/or function lead to reduced bile salt secretion followed by accumulation of bile salts in hepatocytes and hepatocellular damage. This study aimed to detect variations in exons 14, 15, and 24 of the ABCB11 gene in patients with suspected PFIC2 among a group of Egyptian infants and children with normal gamma-glutamyl transpeptidase (GGT) cholestasis. PATIENTS AND METHODS: This observational case-control study was conducted on 13 children with suspected PFIC2 and 13 healthy subjects as controls. Genotyping of the ABCB11 gene was performed via DNA extraction followed by PCR amplification, purification, and then sequencing analysis of exons 14, 15, and 24 of the ABCB11 gene. RESULTS: The study detected two single nucleotide variations, c.1638+ 32T > C (rs2241340) in exon 14 and c.3084A > G (p.Ala1028 = ) (rs497692) in exon 24 of the ABCB11 gene. No variations were identified in exon 15. CONCLUSION: The study revealed two benign variants involving exons 14 and 24 of the ABCB11 gene. Exons 14, 15, and 24 are not hot spots for common mutations in Egyptian PFIC2 patients. Further study of other exons of the ABCB11 gene is necessary to confirm the diagnosis of PFIC2.

The molecular landscape of progressive familial intrahepatic cholestasis in Turkey: Defining the molecular profiles and expanding the variant spectrum.

Progressive familial intrahepatic cholestasis (PFIC) is a rare genetically heterogeneous group of autosomal recessive liver disorders that manifests as intrahepatic cholestasis during the neonatal period. ATP8B1, ABCB11, and ABCB4 genes are responsible for PFIC type 1, PFIC type 2, and PFIC type 3, respectively. To determine the underlying molecular etiology of PFIC, 80 patients from 77 families were investigated. The molecular genetic diagnosis was applied by using next-generation sequencing (NGS) and revealed 29 different variants from 32 patients. In this study, we evaluated these variants according to mechanisms, clinical sub-groups, and genotype-phenotype correlation.

Heterozygous mutations of ATP8B1, ABCB11 and ABCB4 cause mild forms of Progressive Familial Intrahepatic Cholestasis in a pediatric cohort.

INTRODUCTION: Heterozygous defects in genes implicated in Progressive Familial Intrahepatic Cholestasis have been described in milder forms of cholestatic diseases. Our aim is to describe clinical, laboratory and imaging characteristics as well as treatment and outcome of a cohort of pediatric patients with heterozygous mutations in ATP8B1, ABCB11 or ABCB4. PATIENTS AND METHODS: We present a retrospective descriptive study including pediatric patients with at least one heterozygosis defect in ATP8B1, ABCB11 or ABCB4 diagnosed after a cholestatic episode. Clinical, diagnostic and outcome data were collected including gene analysis (panel of PFIC NextGeneDx®). RESULTS: 7 patients showed a heterozygous mutation: 3 patients in ABCB4, 1 in ABCB11, 2 in ABCB4 and ABCB11 and 1 in ATP8B1. The median onset age was 5.5 years with a median time of follow-up of 6 years. The initial presentation was pruritus followed by asymptomatic hypertransaminasemia and persistent cholestasis. Two patients had family history of gallbladder stones and mild hepatitis. All showed elevated transaminases and bile acids, high gamma glutamyl-transferase (GGT) in 3 and conjugated bilirubin in 2 patients. Liver biopsy showed inflammatory infiltrate or mild fibrosis with normal immunohistochemistry. All patients were treated with ursodeoxycholic acid, two patients requiring the addition of resincholestyramine. During follow-up, 3 patients suffered limited relapses of pruritus. No disease progression was observed. CONCLUSION: Heterozygous mutations in genes coding proteins of the hepatocellular transport system can cause cholestatic diseases with great phenotypic variability. The presence of repeated episodes of hypertransaminasemia or cholestasis after a trigger should force us to rule out the presence of these heterozygous mutations in genes involved in CIFP.

Disordered farnesoid X receptor signaling is associated with liver carcinogenesis in Abcb11-deficient mice.

ABCB11 encodes the bile salt export pump (BSEP), a key regulator in maintaining bile acid (BA) homeostasis. Although inherited ABCB11 mutations have previously been linked to primary liver cancer, whether ABCB11 deficiency leads to liver cancer remains unknown. Here, we analyzed ABCB11 mRNA expression levels in liver tumor specimens [29 with hepatocellular carcinoma (HCC), one with intrahepatic cholangiocarcinoma (ICC), and one with mixed HCC/ICC] with adjacent normal specimens and published human datasets. Liver tissues obtained from Abcb11-deficient (Abcb11-/- ) mice and wild-type mice at different ages were compared by histologic, RNA-sequencing, and BA analyses. ABCB11 was significantly downregulated in human liver tumors compared with normal controls. Abcb11-/- mice demonstrated progressive intrahepatic cholestasis and liver fibrosis, and spontaneously developed HCC and ICC over 12 months of age. Abcb11 deficiency increased BAs in the liver and serum in mice, most of which are farnesoid X receptor (FXR) antagonists/non-agonists. Accordingly, the hepatic expression and transcriptional activity of FXR were downregulated in Abcb11-/- mouse livers. Administration of the FXR agonist obeticholic acid reduced liver injury and tumor incidence in Abcb11-/- mice. In conclusion, ABCB11 is aberrantly downregulated and plays a vital role in liver carcinogenesis. The cholestatic liver injury and liver tumors developed in Abcb11-/- mice are associated with increased FXR antagonist BAs and thereby decreased activation of FXR. FXR activation might be a therapeutic strategy in ABCB11 deficiency diseases. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Epidemiology and burden of progressive familial intrahepatic cholestasis: a systematic review.

BACKGROUND: Progressive familial intrahepatic cholestasis is a rare, heterogeneous group of liver disorders of autosomal recessive inheritance, characterised by an early onset of cholestasis with pruritus and malabsorption, which rapidly progresses, eventually culminating in liver failure. For children and their parents, PFIC is an extremely distressing disease. Significant pruritus can lead to severe cutaneous mutilation and may affect many activities of daily living through loss of sleep, irritability, poor attention, and impaired school performance. METHODS: Databases including MEDLINE and Embase were searched for publications on PFIC prevalence, incidence or natural history, and the economic burden or health-related quality of life of patients with PFIC. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. RESULTS: Three systematic reviews and twenty-two studies were eligible for inclusion for the epidemiology of PFIC including a total of 2603 patients. Study periods ranged from 3 to 33 years. Local population prevalence of PFIC was reported in three studies, ranging from 9.0 to 12.0% of children admitted with cholestasis, acute liver failure, or splenomegaly. The most detailed data come from the NAPPED study where native liver survival of >15 years is predicted in PFIC2 patients with a serum bile  acid concentration below 102 µmol/L following bile diversion surgery. Burden of disease was mainly reported through health-related quality of life (HRQL), rates of surgery and survival. Rates of biliary diversion and liver transplant varied widely depending on study period, sample size and PFIC type, with many patients have multiple surgeries and progressing to liver transplant. This renders data unsuitable for comparison. CONCLUSION: Using robust and transparent methods, this systematic review summarises our current knowledge of PFIC. The epidemiological overview is highly mixed and dependent on presentation and PFIC subtype. Only two studies reported HRQL and mortality results were variable across different subtypes. Lack of data and extensive heterogeneity severely limit understanding across this disease area, particularly variation around and within subtypes.

Benign recurrent intrahepatic cholestasis - 2 (BRIC-2)/ABCB11 deficiency in a young child - Report from a tertiary care center in South India.

ABCB11 deficiency, formerly benign recurrent intrahepatic cholestasis (BRIC) is a very rare hereditary disorder characterized by the recurrent and intermittent episodes of cholestasis, jaundice, and pruritus. We report the case of a 12-year-old boy presenting with recurrent episodes of jaundice and severe pruritis since childhood. An extensive workup was done to rule out all the possible etiologies. Liver biopsy was done and histopathology was consistent with intrahepatic cholestasis. Immunohistochemistry, enzyme studies, and genetic testing confirmed the diagnosis. The patient was treated with Ursodeoxycholicacid and is on regular follow-up. We report this case due to the rarity of the disease in South India and to highlight the importance of genetic testing, which is the gold standard for diagnosis as well as for the classification of the disease. These patients should be under regular follow-up as those with fibrosis progression are at a risk for cholangiocarcinoma and hepatocellular carcinoma.

Benign recurrent intrahepatic cholestasis type 2 in a child: A case report and novel mutation.

Benign recurrent intrahepatic cholestasis is a rare disorder characterized by recurrent episodes of cholestatic jaundice without liver damage. A mutation in the ABCB11 gene encoding bile salt export pump protein causes the disease. A 16-year-old boy with severe jaundice is presented here. His laboratory tests were consistent with intrahepatic cholestasis despite having normal gamma-glutamyl transpeptidase levels. Acute and chronic liver diseases with viral, metabolic, and autoimmune etiology were excluded. Magnetic resonance imaging revealed normal intra- and extrahepatic bile ducts. A liver biopsy showed cholestasis in the centrilobular and intermediate zones and sinusoidal dilatation. Genetic testing revealed a homozygous c.3083_3084delCAinsTG (Ala1028Val) mutation in the ABCB11 gene. The patient was treated with ursodeoxycholic acid 20 mg/kg/day and cholestyramine 4 g twice daily, and total bilirubin decreased to normal ranges after two months of therapy. This mutation (c.3083_3084delCAinsTG) in the ABCB11 gene is the first reported in a patient with benign recurrent intrahepatic cholestasis type 2.