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Background: Progressive familial intrahepatic cholestasis (PFIC) is a group of autosomal recessive disorders, the most prevalent being BSEP deficiency, resulting in disrupted bile formation, cholestasis, and pruritus. Building on a previous phase 2 study, we aimed to evaluate the efficacy and safety of maralixibat-an ileal bile acid transporter inhibitor-in participants with all types of PFIC., Methods: MARCH-PFIC was a multicentre, randomised, double-blind, placebo-controlled, phase 3 study conducted in 29 community and hospital centres across 16 countries in Europe, the Americas, and Asia. We recruited participants aged 1-17 years with PFIC with persistent pruritus (>6 months; average of ≥1·5 on morning Itch-Reported Outcome [Observer; ItchRO(Obs)] during the last 4 weeks of screening) and biochemical abnormalities or pathological evidence of progressive liver disease, or both. We defined three analysis cohorts. The BSEP (or primary) cohort included only those with biallelic, non-truncated BSEP deficiency without low or fluctuating serum bile acids or previous biliary surgery. The all-PFIC cohort combined the BSEP cohort with participants with biallelic FIC1, MDR3, TJP2, or MYO5B deficiencies without previous surgery but regardless of bile acids. The full cohort had no exclusions. Participants were randomly assigned (1:1) to receive oral maralixibat (starting dose 142·5 μg/kg, then escalated to 570 μg/kg) or placebo twice daily for 26 weeks. The primary endpoint was the mean change in average morning ItchRO(Obs) severity score between baseline and weeks 15-26 in the BSEP cohort. The key secondary efficacy endpoint was the mean change in total serum bile acids between baseline and the average of weeks 18, 22, and 26 in the BSEP cohort. Efficacy analyses were done in the intention-to-treat population (all those randomly assigned) and safety analyses were done in all participants who received at least one dose of study drug. This completed trial is registered with ClinicalTrials.gov, NCT03905330, and EudraCT, 2019-001211-22., Findings: Between July 9, 2019, and March 4, 2022, 125 patients were screened, of whom 93 were randomly assigned to maralixibat (n=47; 14 in the BSEP cohort and 33 in the all-PFIC cohort) or placebo (n=46; 17 in the BSEP cohort and 31 in the all-PFIC cohort), received at least one dose of study drug, and were included in the intention-to-treat and safety populations. The median age was 3·0 years (IQR 2·0-7·0) and 51 (55%) of 93 participants were female and 42 (45%) were male. In the BSEP cohort, least-squares mean change from baseline in morning ItchRO(Obs) was -1·7 (95% CI -2·3 to -1·2) with maralixibat versus -0·6 (-1·1 to -0·1) with placebo, with a significant between-group difference of -1·1 (95% CI -1·8 to -0·3; p=0·0063). Least-squares mean change from baseline in total serum bile acids was -176 μmol/L (95% CI -257 to -94) for maralixibat versus 11 μmol/L (-58 to 80) for placebo, also representing a significant difference of -187 μmol/L (95% CI -293 to -80; p=0·0013). The most common adverse event was diarrhoea (27 [57%] of 47 patients on maralixibat vs nine [20%] of 46 patients on placebo; all mild or moderate and mostly transient). There were five (11%) participants with serious treatment-emergent adverse events in the maralixibat group versus three (7%) in the placebo group. No treatment-related deaths occurred., Interpretation: Maralixibat improved pruritus and predictors of native liver survival in PFIC (eg, serum bile acids). Maralixibat represents a non-surgical, pharmacological option to interrupt the enterohepatic circulation and improve the standard of care in patients with PFIC., Funding: Mirum Pharmaceuticals., Competing Interests: Declaration of interests AGM is a consultant and has a sponsored research agreement with Mirum Pharmaceuticals. JCE has received support to his institution from Mirum Pharmaceuticals. PC is a consultant for Ipsen-Albireo. FO is a speaker for Alexion Pharmaceuticals and Valentech Pharma. AAA is a consultant and adviser for Mirum Pharmaceuticals and Ipsen-Albireo. ES is the founder and chairperson of Cellaion; an investigator for Mirum Pharmaceuticals, Albireo, and Intercept; and an adviser for Mirum Pharmaceuticals and Albireo. UB is a consultant for and has received research funding from Mirum Pharmaceuticals, Ipsen-Albireo, Nestle, and Vivet Pharmaceuticals; and has served as a speaker for Mirum Pharmaceuticals and Ipsen-Alibreo. LD is a consultant and adviser for Mirum Pharmaceuticals, Albireo, Selecta, Vivet Pharmaceuticals, Tome, Spark, Genespire, and Alexion. NK is a consultant for Mirum Pharmaceuticals. C-HL has received a research grant from Mirum Pharmaceuticals. SG is an adviser for and has received research support to her institution from Mirum Pharmaceuticals. NM is an investigator for Mirum Pharmaceuticals. SPH is a hepatic safety adjudication committee member at Ipsen-Albireo and has received a research grant from Mirum Pharmaceuticals. TJ is a shareholder and has intellectual property rights in Mirum Pharmaceuticals, and is an employee of and shareholder in Galapagos. VFH is a consultant for and has received research support to her institution from Mirum Pharmaceuticals. RPG-P has received a research grant from Mirum Pharmaceuticals, and is an adviser, teacher, and educator for Mirum Pharmaceuticals and Albireo. UE is a steering committee member for Mirum Pharmaceuticals. JH has received a research grant from Mirum Pharmaceuticals. NO has received research support to her institution from Mirum Pharmaceuticals, Albireo, and Travere. RJT is a consultant, adviser, and speaker for and has received research support to his institution from Mirum Pharmaceuticals. TN, AL, LL, DBM, WG, and PV are employees of and shareholders in Mirum Pharmaceuticals. AMou, GP, AMos, RHS, DD, NLab, CA, FKC, W-DH, and NLav declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Objectives: Biallelic variants in the adenosine triphosphate binding cassette subfamily B member 4 (ABCB4) gene which encodes the multidrug resistance 3 protein (MDR3) leads to progressive familiar intrahepatic cholestasis type 3. However, monoallelic variants are increasingly recognized as contributing to liver disease in adults. Our aim was to describe the clinical characteristics of MDR3 heterozygous variants in a large cohort of infants and children with cholestatic liver disease., Methods: The clinical and genotypic data on pediatric patients seen at King's College Hospital, London, between 2004 and 2022 and found to harbour heterozygous variants in ABCB4 were reviewed., Results: Ninety-two patients amongst 1568 tested were identified with a monoallelic variant (5.9%). The most common presenting problem was conjugated hyperbilirubinemia (n = 46; 50%) followed by cholelithiasis (n = 12; 13%) and cholestatic hepatitis (n = 10; 11%). The median values of liver biochemistry at presentation were: GGT 105 IU/L and total bilirubin 86 µmol/L. Thirty-two genetic variants were identified including 22 missense (69%), 4 deletions (13%), 5 splice site (16%) and 1 termination (3%). At a median follow up of 1 year there was resolution of liver disease., Conclusions: Rare variants in ABCB4 were found amongst infants and children with cholestatic liver disease. The presenting problems were variable and abnormalities tended to normalize over time. Those with severe mutations could develop liver disease later in life when exposed to further insult and should be counseled appropriately., (© 2023 The Authors. Journal of Pediatric Gastroenterology and Nutrition published by Wiley Periodicals LLC on behalf of European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Variants in ATP8B1, ABCB11, and ABCB4 underlie the most prevalent forms of progressive familial intrahepatic cholestasis. We aim to describe variants in these genes in a cohort of patients with adult-onset liver disease, and explore a genotype-phenotype correlation. Patients with onset of liver disease aged above 18 who underwent sequencing of cholestasis genes for clinical purposes over a 5-year period were identified. Bioinformatic analysis of variants was performed. Liver histology was evaluated in patients with variants. Of the 356 patients tested, at least one variant was identified in 101 (28.4%): 46 ABCB4, 35 ABCB11, and 28 ATP8B1. Patients with ABCB4 variants had chronic liver disease (71.7%) and pregnancy-associated liver dysfunction (75%), with a younger age of onset in more severe genotypes (p = 0.046). ABCB11 variants presented with pregnancy-associated liver dysfunction (82.4%) and acute/episodic cholestasis (40%), with no association between age of onset and genotype severity. ATP8B1 variants were associated with chronic liver disease (75%); however, they were commonly seen in patients with an alternate etiology of liver disease and variants were of low predicted pathogenicity. In adults with suspected genetic cholestasis, variants in cholestasis genes were frequently identified and were likely to contribute to the development of liver disease, particularly ABCB4 and ABCB11. Variants were often in heterozygous state, and they should no longer be considered recessive Mendelian traits. Sequencing cholestasis genes in selected patients with adult-onset disease should be considered, with interpretation in close collaboration with histopathologists and geneticists., (© 2022 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)

Children with progressive familial intrahepatic cholestasis, including bile salt export pump (BSEP) and familial intrahepatic cholestasis-associated protein 1 (FIC1) deficiencies, suffer debilitating cholestatic pruritus that adversely affects growth and quality of life (QoL). Reliance on surgical interventions, including liver transplantation, highlights the unmet therapeutic need. INDIGO was an open-label, Phase 2, international, long-term study to assess the efficacy and safety of maralixibat in children with FIC1 or BSEP deficiencies. Thirty-three patients, ranging from 12 months to 18 years of age, were enrolled. Eight had FIC1 deficiency and 25 had BSEP deficiency. Of the latter, 6 had biallelic, protein truncating mutations (t)-BSEP, and 19 had ≥ 1 nontruncating mutation (nt)-BSEP. Patients received maralixibat 266 μg/kg orally, once daily, from baseline to Week 72, with twice-daily dosing permitted from Week 72. Long-term efficacy was determined at Week 240. Serum bile acid (sBA) response (reduction in sBAs of > 75% from baseline or concentrations <102.0 μmol/L) was achieved in 7 patients with nt-BSEP, 6 during once-daily dosing, and 1 after switching to twice-daily dosing. sBA responders also demonstrated marked reductions in sBAs and pruritus, and increases in height, weight, and QoL. All sBA responders remained liver transplant-free after > 5 years. No patients with FIC1 deficiency or t-BSEP deficiency met the sBA responder criteria during the study. Maralixibat was generally well-tolerated throughout the study. Conclusion: Response to maralixibat was dependent on progressive familial intrahepatic cholestasis subtype, and 6 of 19 patients with nt-BSEP experienced rapid and sustained reductions in sBA levels. The 7 responders survived with native liver and experienced clinically significant reductions in pruritus and meaningful improvements in growth and QoL. Maralixibat may represent a well-tolerated alternative to surgical intervention., (© 2022 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)

Background: Progressive familial intrahepatic cholestasis (PFIC) is a group of inherited paediatric liver diseases resulting from mutations in genes that impact bile secretion. We aimed to evaluate the effects of odevixibat, an ileal bile acid transporter inhibitor, versus placebo in children with PFIC., Methods: Patients eligible for this 24-week, randomised, double-blind, completed, phase 3 study were paediatric outpatients diagnosed with PFIC1 or PFIC2 who had pruritus and elevated serum bile acids at screening. Patients were randomly assigned (1:1:1) using an interactive web-based system to once a day oral placebo, odevixibat 40 μg/kg, or odevixibat 120 μg/kg. Randomisation was done in a block size of six and stratified by PFIC type and patient age; patients, clinicians, and study staff were blinded to treatment allocation. Patients were enrolled at one of 33 global sites. Two primary endpoints were evaluated: proportion of positive pruritus assessments (PPAs; ie, scratching score of ≤1 or ≥1-point decrease as assessed by caregivers using the Albireo observer-reported outcome [ObsRO] PRUCISION instrument) over 24 weeks, and proportion of patients with serum bile acid response (ie, serum bile acids reduced by ≥70% from baseline or concentrations of ≤70 μmol/L) at week 24. Efficacy and safety were analysed in randomly allocated patients who received one or more doses of study drug. This study is registered with ClinicalTrials.gov, NCT03566238., Findings: Between June 21, 2018, and Feb 10, 2020, 62 patients (median age 3·2 [range 0·5-15·9] years) were randomly allocated to placebo (n=20), odevixibat 40 μg/kg per day (n=23), or odevixibat 120 μg/kg per day (n=19). Model-adjusted (least squares) mean proportion of PPAs was significantly higher with odevixibat versus placebo (55% [SE 8] in the combined odevixibat group [58% in the 40 μg/kg per day group and 52% in the 120 μg/kg per day group] vs 30% [SE 9] in the placebo group; model-adjusted mean difference 25·0% [95% CI 8·5-41·5]; p=0·0038). The percentage of patients with serum bile acid response was also significantly higher with odevixibat versus placebo (14 [33%] of 42 patients in the combined odevixibat group [10 in the 40 μg/kg per day group and four in the 120 μg/kg per day group] vs none of 20 in the placebo group; adjusting for stratification factor [PFIC type], the proportion difference was 30·7% [95% CI 12·6-48·8; p=0·0030]). The most common treatment-emergent adverse events (TEAEs) were diarrhoea or frequent bowel movements (13 [31%] of 42 for odevixibat vs two [10%] of 20 for placebo) and fever (12 [29%] of 42 vs five [25%] of 20); serious TEAEs occurred in three (7%) of 42 odevixibat-treated patients and in five (25%) of 20 placebo-treated patients., Interpretation: In children with PFIC, odevixibat effectively reduced pruritus and serum bile acids versus placebo and was generally well tolerated. Odevixibat, administered as once a day oral capsules, is a non-surgical, pharmacological option to interrupt the enterohepatic circulation in patients with PFIC., Funding: Albireo Pharma., Competing Interests: Declaration of interests RJT is a consultant at Albireo, Generation Bio, Mirum, and Rectify and is a stockholder at Generation Bio and Rectify. HA is an advisor at Mirum and receives honoraria from Baxter Healthcare. UB is a consultant at Albireo and Mirum. PC is an investigator with clinical trial contracts at Mirum and Albireo. LD is a consultant at Albireo. EG is a consultant at Albireo, CTRS Laboratories, Mirum, and Vivet; and advisory board member at Albireo and Mirum. BMK is a consultant at Albireo, Audentes and Mirum and receives unrestricted educational grants to SickKids Foundation from Albireo and Mirum. SJK is a consultant at Albireo, Intercept, and Mirum. LK is a former employee and stockholder at Albireo. EL is a treasurer of GPGE congress, receives honoraria for presentation from Albireo, and participated in the PEDFIC 1 clinical trial. JPM is an employee and stockholder at Albireo, and has a patent planned and pending at Albireo. ESt reports grants paid to institution from Albireo and Mirum; honoraria from Albireo (paid to institution), Mirum, Univar, and GMP Orphan; travel support from Albireo, Mirum, and Astellas; he is a consultant at Mirum and advisor at Albireo, and Mirum. HJV reports grants to institution from Albireo and Mirum; consultant fees paid to institution from Ausnutria BV, Albireo, Danone/Nutricia Research, Intercept, Mirum, Orphalan, and Vivet; advisor fees paid to institution from Albireo and Mirum; and unpaid leadership role at Medical Advisory Board PFIC Network. PH is a former employee and stockholder at Albireo. All other authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Purpose: Ileal bile acid transporter inhibition is a novel therapeutic concept for cholestatic pruritus and cholestatic liver disease progression. Odevixibat, a potent, selective, reversible ileal bile acid transporter inhibitor, decreases enteric bile acid reuptake with minimal systemic exposure. Oral odevixibat safety, tolerability, and efficacy in pediatric patients with cholestatic liver disease and pruritus were evaluated., Patients and Methods: In this phase 2, open-label, multicenter study, children received 10‒200 μg/kg oral odevixibat daily for 4 weeks. Changes in serum bile acid levels (primary efficacy endpoint), pruritus, and sleep disturbance were explored., Results: Twenty patients were enrolled (8 females; 1‒17 years; 4 re-entered at a different dose). Diagnoses included progressive familial intrahepatic cholestasis (n = 13; 3 re-entries), Alagille syndrome (n = 6), biliary atresia (n = 3), and other intrahepatic cholestasis causes (n = 2; 1 re-entry). Mean baseline serum bile acid levels were high (235 µmol/L; range, 26‒564) and were reduced in the majority (-123.1 μmol/L; range, -394 to 14.5, reflecting reductions of up to 98%). Patient-reported diary data documented improved pruritus (3 scales) and sleep. With 100 μg/kg, mean (SEM) decrease was 2.8 (1.1) points for pruritus (visual analogue itch scale 0-10) and 2.9 (0.9) points for sleep disturbance (Patient-Oriented Scoring Atopic Dermatitis scale 0-10). Reduced pruritus correlated significantly with reduced serum bile acids (P ≤ 0.007). Significant correlations were also observed between autotaxin levels and pruritus. All patients completed the study. No serious adverse events were treatment related; most adverse events, including increased transaminases, were transient., Conclusions: Orally administered odevixibat was well tolerated, reduced serum bile acids, and improved pruritus and sleep disturbance in children with cholestatic diseases., (Copyright © 2021. Published by Elsevier Masson SAS.)

Objectives: To advance our understanding of monogenic forms of intrahepatic cholestasis., Methods: Analyses included participants with pathogenic biallelic mutations in adenosine triphosphate (ATP)-binding cassette subfamily B member 11 (ABCB11) (bile salt export pump; BSEP) or adenosine triphosphatase (ATPase) phospholipid transporting 8B1 (ATP8B1) (familial intrahepatic cholestasis; FIC1), or those with monoallelic or biallelic mutations in adenosine triphosphate (ATP)-binding cassette subfamily B member 4 (ABCB4) (multidrug resistance; MDR3), prospectively enrolled in the Longitudinal Study of Genetic Causes of Intrahepatic Cholestasis (LOGIC; NCT00571272) between November 2007 and December 2013. Summary statistics were calculated to describe baseline demographics, history, anthropometrics, laboratory values, and mutation data., Results: Ninety-eight participants with FIC1 (n = 26), BSEP (n = 53, including 8 with biallelic truncating mutations [severe] and 10 with p.E297G or p.D482G [mild]), or MDR3 (n = 19, including four monoallelic) deficiency were analyzed. Thirty-five had a surgical interruption of the enterohepatic circulation (sEHC), including 10 who underwent liver transplant (LT) after sEHC. Onset of symptoms occurred by age 2 years in most with FIC1 and BSEP deficiency, but was later and more variable for MDR3. Pruritus was nearly universal in FIC1 and BSEP deficiency. In participants with native liver, failure to thrive was common in FIC1 deficiency, high ALT was common in BSEP deficiency, and thrombocytopenia was common in MDR3 deficiency. sEHC was successful after more than 1 year in 7 of 19 participants with FIC1 and BSEP deficiency. History of LT was most common in BSEP deficiency. Of 102 mutations identified, 43 were not previously reported., Conclusions: In this cohort, BSEP deficiency appears to be correlated with a more severe disease course. Genotype-phenotype correlations in these diseases are not straightforward and will require the study of larger cohorts., Competing Interests: Conflicts of Interest: R.J.T. consults for Albireo Pharma, Alnylam, EVOX Therapeutics, GenerationBio, Horizon Pharma, Mirum Pharma, Qing Bile Therapeutics, Retrophin, and Sana Biotechnology. He has shared options in GenerationBio and Qing Bile Therapeutics. S.P.H. reports participation in the Mirum maralixibat PFIC trials—research grants only paid to the institution. M.S.C. reports participation in the Bolder Surgical, Inc. (Louisville, CO) Physician Advisory Board. K.M.L. declares consulting relationships and research grants from Mirum Pharmaceuticals and Albireo Pharma. B.M.K. reports she is a consultant and has unrestricted educational grants from Albireo and Mirum. For all remaining coauthors, no conflicts of interest are declared., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Background and Aims: Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date., Approach and Results: This multicenter, combined retrospective and prospective study included 130 patients with compound heterozygous or homozygous predicted pathogenic ATP8B1 variants. Patients were categorized according to the number of PPTMs (i.e., splice site, frameshift due to deletion or insertion, nonsense, duplication), FIC1-A (n = 67; no PPTMs), FIC1-B (n = 29; one PPTM), or FIC1-C (n = 34; two PPTMs). Survival analysis showed an overall native liver survival (NLS) of 44% at age 18 years. NLS was comparable among FIC1-A, FIC1-B, and FIC1-C (% NLS at age 10 years: 67%, 41%, and 59%, respectively; P = 0.12), despite FIC1-C undergoing SBD less often (% SBD at age 10 years: 65%, 57%, and 45%, respectively; P = 0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10 years, sBAs < 194 µmol/L: 49% vs. sBAs ≥ 194 µmol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] μmol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 μmol/L (P = 0.05) tended to be associated with improved NLS., Conclusions: Less than half of patients with FIC1 deficiency reach adulthood with native liver. The number of PPTMs did not associate with the natural history or prognosis of FIC1 deficiency. sBA concentrations at initial presentation and after SBD provide limited prognostic information on long-term NLS., (© The Authors. Hepatology published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)

Objectives: Although a number of genetic forms of cholestasis have been identified, the genetic etiology of disease remains unidentified in a subset of cholestasis patients., Methods: Whole exome sequencing (WES) was performed in DNA from patients diagnosed with cholestasis, at different points on the continuum from progressive familial intrahepatic cholestasis to benign recurrent intrahepatic cholestasis, in whom no disease mutations in known cholestasis genes had been identified. Candidate genes were then assessed in a larger patient sample, by targeted next-generation sequencing (NGS). Disease features at presentation and follow-up were collected from available medical records., Results: By WES, we identified 3 patients with homozygous mutations in USP53. Screening of USP53 in a larger set of patients identified 4 additional patients with homozygous mutations in USP53. Six of the 7 patients had deletion mutations, and 1 had a missense mutation; 3 of the patients were siblings, all bearing a deletion that also disrupted neighboring MYOZ2. Age of onset ranged from early infancy to adolescence. Cholestasis tended to be biochemically mild and intermittent, and responsive to medication. Liver fibrosis was, however, present in all 4 patients who were biopsied, and splenomegaly was apparent in 5 of 7 at last ultrasound., Conclusions: Two groups recently identified patients with liver disease and mutation in USP53. We have now identified biallelic mutation in USP53 in 7 further patients with cholestasis, from 5 families. Most individuals had evidence of chronic liver disease, and long-term follow-up is recommended., Competing Interests: R.J.T. consults for Albireo, Mirum, GenerationBio, Alnylam, Qing Bile, Horizon, Sana, and Retrophin and has share options in Qing Bile and GenerationBio. Other authors report no conflicts of interest. M.S. is now an employee of Illumina Inc., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Objectives: Mutations in Myosin 5B (MYO5B) are known to be associated with microvillous inclusion disease (MVID) a genetic cause of neonatal intractable diarrhoea. More recently, they have been reported in children with cholestasis but without typical gastrointestinal symptoms of MVID. We describe our series of children with cholestasis and mutations in MYO5B., Methods: Clinical, laboratory, and histological data were collected from patients with cholestasis and pathogenic mutations in MYO5B, found by next generation sequencing (NGS) but with minimal gastrointestinal disease., Results: Six patients (3 boys) were identified. Median age at presentation was 19 months (range, 3-92). Presenting features were jaundice, pale stools, pruritus, and failure to thrive. Patients 5 and 6 had intractable diarrhoea until the age of 3 and 7 years, respectively, but currently are on full enteral diet with no intestinal symptoms. Median values for serum total bilirubin were 55 μmol/L (2-500), alanine aminotransferase 73I IU/L (32-114), γ-glutamyltransferase 7 IU/L (7-10), and serum bile acids 134 μmol/L (18-274). Three patients underwent 1 or more types of biliary diversion for symptom control. Median follow-up was 5 years (2-22). At most recent follow-up, they all reported pruritus while on antipruritics. Patient 1 had a liver transplant., Conclusions: We identified 6 patients, with mutations in MYO5B, early-onset cholestasis and pruritus, with variable response to biliary diversion without typical MVID.

Objectives: We assessed available data on impact of partial external biliary diversion (PEBD) surgery on clinical outcomes in patients with progressive familial intrahepatic cholestasis (PFIC)., Methods: We performed a systematic literature review (PubMed) and meta-analysis to evaluate relationships between liver biochemistry parameters (serum bile acids, bilirubin, and alanine aminotransferase [ALT]) and early response (pruritus improvement) or long-term outcomes (need for liver transplant) in patients with PFIC who underwent PEBD., Results: Searches identified 175 publications before September 2018; 16 met inclusion criteria. Receiver operating characteristic (ROC) analysis examined ability of liver biochemistry parameters to discriminate patients who demonstrated early and long-term response to PEBD from those who did not. Regarding pruritus improvement in 155 included patients in aggregate, 104 (67%) were responders, 14 (9%) had partial response, and 37 (24%) were nonresponders. In ROC analyses of individual patient data, post-PEBD serum concentration of bile acids, in particular, could discriminate responders from nonresponders for pruritus improvement (area under the curve, 0.99; P < 0.0001; n = 42); to a lesser extent, this was also true for bilirubin (0.87; P = 0.003; n = 31), whereas ALT could not discriminate responders from nonresponders for pruritus improvement (0.74; P = 0.06; n = 28). Reductions from pre-PEBD values in serum bile acid concentration (0.89; P = 0.0003; n = 32) and bilirubin (0.98; P = 0.002; n = 18) but not ALT (0.62; P = 0.46; n = 18) significantly discriminated decreased aggregate need for liver transplant., Conclusion: Changes in bile acids seem particularly useful in discriminating early and long-term post-PEBD outcomes and may be potential biomarkers of response to interruption of enterohepatic circulation in patients with PFIC.

Background & Aims: Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date., Methods: This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category., Results: Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27-0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 μmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001)., Conclusions: The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS., Lay Summary: This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease., Competing Interests: Conflicts of interest Daan B.E. van Wessel: [nothing to disclose], Richard J. Thompson [consultancy for Shire, Albireo, Mirum, Horizon Pharmaceuticals, Sana Biotechnology, GenerationBio, Retrophin and Qing Bile Therapeutics], Emmanuel M. Gonzales [Consultant for CTRS and Mirum Pharmaceuticals], Irena Jankowska [nothing to disclose], Tassos Grammatikopoulos [nothing to disclose], Agustina Kadaristiana [nothing to disclose], Patryk Lipiński [nothing to disclose], Piotr Czubkowski [nothing to disclose], Nathalie Rock [nothing to disclose] Emmanuel Jacquemin [nothing to disclose], Anne Spraul [nothing to disclose], Etienne M. Sokal [founder and CSMO of Promethera Biosciences], Mohammad Shagrani [nothing to disclose], Dieter Broering [nothing to disclose], Talal Algoufi [nothing to disclose], Nejat Mazhar [nothing to disclose], Emanuele Nicastro [nothing to disclose] Deirdre Kelly [Consultant for Albireo], Gabriela Nebbia [nothing to disclose], Henrik Arnell [consultant for Albireo and Mirum Pharmaceuticals], Björn Fischler [has attended one advisory board meeting with Albireo in 2016], Jan Hulscher [nothing to disclose], Daniele Serranti [nothing to disclose], Cigdem Arikan [nothing to disclose], Esra Polat [nothing to disclose], Dominique Debray [consultant for Alexion pharmaceuticals], Florence Lacaille [nothing to disclose], Cristina Goncalves [nothing to disclose], Loreto Hierro [nothing to disclose], Gema Muñoz Bartolo [nothing to disclose], Yael Mozer-Glassberg [nothing to disclose], Amer Azaz [nothing to disclose], Jernej Brecelj [nothing to disclose], Antal Dezsőfi [nothing to disclose], Pier Luigi Calvo [nothing to disclose], Enke Grabhorn [nothing to disclose], Ekkehard Sturm [nothing to disclose] Wendy van der Woerd [nothing to disclose], Binita Kamath [consultant for Mirum Pharmaceuticals, Shire and DCI], Jian-She Wang [nothing to disclose], Liting Li [nothing to disclose], Özlem Durmaz [nothing to disclose], Zerrin Onal [nothing to disclose], Ton Bunt [nothing to disclose], Bettina Hansen [consultant for Mirum Pharmaceuticals, Albireo AB, Chemomab, Calliditas, Intercept, Cyma Bay, unrestricted grants from Cyma bay, Intercept, Mirum and Albireo], Henkjan J. Verkade [Consultant for Danone/Nutricia Research, Ausnutria BV, Albireo AB, GMP+Orphan, Mirum Pharmaceuticals, Intercept and Vivet]. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2020 European Association for the Study of the Liver. All rights reserved.)

Genetic cholestasis has been dissected through genetic investigation. The major PFIC genes are now described. ATP8B1 encodes FIC1, ABCB11 encodes BSEP, ABCB4 encodes MDR3, TJP2 encodes TJP2, NR1H4 encodes FXR, and MYO5B encodes MYO5B. The full spectra of phenotypes associated with mutations in each gene are discussed, along with our understanding of the disease mechanisms. Differences in treatment response and targets for future treatment are emerging., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: To assess whether prolonged neonatal cholestasis, described in congenital hypopituitarism and septo-optic dysplasia (SOD), is associated with altered expression of selected canalicular ectoenzymes and canalicular transport proteins., Study Design: Children with congenital hypopituitarism (n = 21), SOD (n = 18), and cholestasis seen in our center over 26 years were reviewed. Histopathologic findings in archival liver biopsy specimens were assessed (n = 10) and in those with low/normal levels of serum γ-glutamyltransferase (GGT) activity despite conjugated hyperbilirubinemia, expression of canalicular ectoenzymes and canalicular transport proteins was evaluated immunohistochemically., Results: Patients presented at a median age of 8 weeks (range 3-20 weeks) with median total bilirubin 116 µmol/L (45-287 µmol/L), GGT 95 IU/L (25-707 UI/L), and serum cortisol 51 nmol/L (17-240 nmol/L). All but 3 had low free thyroxin (median 9.6 pmol/L [6.8-26.9]) with increased thyroid-stimulating hormone levels (median 5.95 mU/L [<0.1-9.24]). Liver histologic features included moderate-to-severe intralobular cholestasis with nonspecific hepatitis, giant-cell transformation of hepatocytes, and fibrosis. In all, immunohistochemical staining for canalicular ectoenzymes and canalicular transport proteins revealed a degree of reduced expression, associated with normal serum GGT values in 6 of the 10 patients, and another 6 nonbiopsied infants with cholestasis also had low/normal serum GGT activity. Sequencing of ABCB11 and ATP8B1 performed in 6 of the biopsied patients did not identify pathogenic mutations. Following replacement therapy, biochemical evidence of hepatobiliary injury resolved in all children within a median period of 6 months., Conclusion: Hepatobiliary involvement in congenital hypopituitarism associated with SOD has a good prognosis, but its etiology remains uncertain. Immunohistochemical expression of canalicular transport proteins was reduced in available liver samples., (Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.)

Intrahepatic cholestasis of pregnancy (ICP) affects 1/140 UK pregnancies; with pruritus, hepatic impairment and elevated serum bile acids. Severe disease is complicated by spontaneous preterm delivery and stillbirth. Previous studies have reported mutations in hepatocellular transporters (ABCB4, ABCB11). High throughput sequencing in 147 patients was performed in the transporters ABCB4, ABCB11, ATP8B1, ABCC2 and tight junction protein 2 (TJP2). Twenty-six potentially damaging variants were identified with the following predicted protein changes: Twelve ABCB4 mutations - Arg47Gln, Met113Val, Glu161Gly, Thr175Ala, Glu528Glyfs*6, Arg590Gln, Ala601Ser, Glu884Ter, Gly722Ala, Tyr775Met (x2), Trp854Ter. Four potential ABCB11 mutations - Glu297Gly (x3) and a donor splice site mutation (intron 19). Five potential ATP8B1 mutations - Asn45Thr (x3), and two others, Glu114Gln and Lys203Glu. Two ABCC2 mutations - Glu1352Ala and a duplication (exons 24 and 25). Three potential mutations were identified in TJP2; Thr62Met (x2) and Thr626Ser. No patient harboured more than one mutation. All were heterozygous. An additional 545 cases were screened for the potential recurrent mutations of ATP8B1 (Asn45Thr) and TJP2 (Thr62Met) identifying three further occurrences of Asn45Thr. This study has expanded known mutations in ABCB4 and ABCB11 and identified roles in ICP for mutations in ATP8B1 and ABCC2. Possible novel mutations in TJP2 were also discovered.

Hepatocellular carcinoma (HCC) is almost invariably associated with an underlying inflammatory state, whose direct contribution to the acquisition of critical genomic changes is unclear. Here we map acquired genomic alterations in human and mouse HCCs induced by defects in hepatocyte biliary transporters, which expose hepatocytes to bile salts and cause chronic inflammation that develops into cancer. In both human and mouse cancer genomes, we find few somatic point mutations with no impairment of cancer genes, but massive gene amplification and rearrangements. This genomic landscape differs from that of virus- and alcohol-associated liver cancer. Copy-number gains preferentially occur at late stages of cancer development and frequently target the MAPK signalling pathway, and in particular direct regulators of JNK. The pharmacological inhibition of JNK retards cancer progression in the mouse. Our study demonstrates that intrahepatic cholestasis leading to hepatocyte exposure to bile acids and inflammation promotes cancer through genomic modifications that can be distinguished from those determined by other aetiological factors.

Elucidating genetic causes of cholestasis has proved to be important in understanding the physiology and pathophysiology of the liver. Here we show that protein-truncating mutations in the tight junction protein 2 gene (TJP2) cause failure of protein localization and disruption of tight-junction structure, leading to severe cholestatic liver disease. These findings contrast with those in the embryonic-lethal knockout mouse, highlighting differences in redundancy in junctional complexes between organs and species.

Background & Aims: Progressive familial intrahepatic cholestasis (PFIC) with normal serum levels of gamma-glutamyltranspeptidase can result from mutations in ATP8B1 (encoding familial intrahepatic cholestasis 1 [FIC1]) or ABCB11 (encoding bile salt export pump [BSEP]). We evaluated clinical and laboratory features of disease in patients diagnosed with PFIC, who carried mutations in ATP8B1 (FIC1 deficiency) or ABCB11 (BSEP deficiency). Our goal was to identify features that distinguish presentation and course of these two disorders, thus facilitating diagnosis and elucidating the differing consequences of ATP8B1 and ABCB11 mutations., Methods: A retrospective multi-center study was conducted, using questionnaires and chart review. Available clinical and biochemical data from 145 PFIC patients with mutations in either ATP8B1 (61 "FIC1 patients") or ABCB11 (84 "BSEP patients") were evaluated., Results: At presentation, serum aminotransferase and bile salt levels were higher in BSEP patients; serum alkaline phosphatase values were higher, and serum albumin values were lower, in FIC1 patients. Elevated white blood cell counts, and giant or multinucleate cells at liver biopsy, were more common in BSEP patients. BSEP patients more often had gallstones and portal hypertension. Diarrhea, pancreatic disease, rickets, pneumonia, abnormal sweat tests, hearing impairment, and poor growth were more common in FIC1 patients. Among BSEP patients, the course of disease was less rapidly progressive in patients bearing the D482G mutation., Conclusions: Severe forms of FIC1 and BSEP deficiency differed. BSEP patients manifested more severe hepatobiliary disease, while FIC1 patients showed greater evidence of extrahepatic disease., (Copyright 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Background: Partial External Biliary Diversion (PEBD) is a surgical intervention to treat children with Progressive Familial Intrahepatic Cholestasis (PFIC) and Alagille syndrome (AGS). PEBD can reduce disease progression, and examining the alterations in biliary lipid composition may be a prognostic factor for outcome., Methods: Biliary lipid composition and the clinical course of AGS and PFIC patients were examined before and after PEBD., Results: Pre-PEBD bile from AGS patients had greater chenodeoxycholic/cholic acid (CDCA/CA), bile salt, cholesterol and phospholipid concentrations than PFIC patients. AGS patients, and PFIC patients with familial intrahepatic cholestasis 1 (FIC1) genotype, responded better to PEBD than PFIC patients with bile salt export protein (BSEP) genotype. After successful PEBD, AGS patients have higher biliary lipid concentrations than PFIC patients and PEBD also increases biliary phospholipid concentrations in FIC1 patients., Conclusion: Both AGS and FIC1 patients can benefit from PEBD, and preserved biliary phospholipid concentrations may be associated with better outcomes post-PEBD.

Background & Aims: Patients with severe bile salt export pump (BSEP) deficiency present as infants with progressive cholestatic liver disease. We characterized mutations of ABCB11 (encoding BSEP) in such patients and correlated genotypes with residual protein detection and risk of malignancy., Methods: Patients with intrahepatic cholestasis suggestive of BSEP deficiency were investigated by single-strand conformation polymorphism analysis and sequencing of ABCB11. Genotypes sorted by likely phenotypic severity were correlated with data on BSEP immunohistochemistry and clinical outcome., Results: Eighty-two different mutations (52 novel) were identified in 109 families (9 nonsense mutations, 10 small insertions and deletions, 15 splice-site changes, 3 whole-gene deletions, 45 missense changes). In 7 families, only a single heterozygous mutation was identified despite complete sequence analysis. Thirty-two percent of mutations occurred in >1 family, with E297G and/or D482G present in 58% of European families (52/89). On immunohistochemical analysis (88 patients), 93% had abnormal or absent BSEP staining. Expression varied most for E297G and D482G, with some BSEP detected in 45% of patients (19/42) with these mutations. Hepatocellular carcinoma or cholangiocarcinoma developed in 15% of patients (19/128). Two protein-truncating mutations conferred particular risk; 38% (8/21) of such patients developed malignancy versus 10% (11/107) with potentially less severe genotypes (relative risk, 3.7 [confidence limits, 1.7-8.1; P = .003])., Conclusions: With this study, >100 ABCB11 mutations are now identified. Immunohistochemically detectable BSEP is typically absent, or much reduced, in severe disease. BSEP deficiency confers risk of hepatobiliary malignancy. Close surveillance of BSEP-deficient patients retaining their native liver, particularly those carrying 2 null mutations, is essential.