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Maha Saleh,1 Binita M Kamath,2 David Chitayat1,3 1Division of Clinical and Metabolic Genetics, 2Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, The Hospital for Sick Children, 3Department of Obstetrics and Gynecology, Prenatal Diagnosis and Medical Genetics Program, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada Abstract: Alagille syndrome is an autosomal dominant, complex multisystem disorder characterized by the presence of three out of five major clinical criteria: cholestasis with bile duct paucity on liver biopsy, congenital cardiac defects (with particular involvement of the pulmonary arteries), posterior embryotoxon in the eye, characteristic facial features, and butterfly vertebrae. Renal and vascular abnormalities can also occur. Inter- and intrafamilial variabilities in the clinical manifestations are common. We reviewed the clinical features and management as well as the molecular basis of Alagille syndrome. Keywords: Alagille syndrome, ALGS, genetics, liver

Purpose of Review: To highlight recent advances in pediatric cholestatic liver disease, including promising novel prognostic markers and new therapies., Findings: Additional genetic variants associated with the progressive familial intrahepatic cholestasis (PFIC) phenotype and new genetic cholangiopathies, with an emerging role of ciliopathy genes, are increasingly being identified. Genotype severity predicts outcomes in bile salt export pump (BSEP) deficiency, and post-biliary diversion serum bile acid levels significantly affect native liver survival in BSEP and progressive familial intrahepatic cholestasis type 1 (FIC1 deficiency) patients. Heterozygous variants in the MDR3 gene have been associated with various cholestatic liver disease phenotypes in adults. Ileal bile acid transporter (IBAT) inhibitors, approved for pruritus in PFIC and Alagille Syndrome (ALGS), have been associated with improved long-term quality of life and event-free survival., Summary: Next-generation sequencing (NGS) technologies have revolutionized diagnostic approaches, while discovery of new intracellular signaling pathways show promise in identifying therapeutic targets and personalized strategies. Bile acids may play a significant role in hepatic damage progression, suggesting their monitoring could guide cholestatic liver disease management. IBAT inhibitors should be incorporated early into routine management algorithms for pruritus. Data are emerging as to whether IBAT inhibitors are impacting disease biology and modifying the natural history of the cholestasis., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Aims: Autoimmune hepatitis (AIH) in children presenting in acute liver failure (ALF) can be fatal and often requires liver transplantation (LTx). This individual patient data meta-analysis (IPD) aims to examine management and outcomes of this population, given the lack of large cohort studies on paediatric AIH first presenting as ALF (AIH-ALF)., Methods: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses of IPD statement using PubMed and Excerpta Medica dataBASE, and included English studies published between 2000 and 2020. The study included patients under 21 years of age, diagnosed with type 1 or 2 AIH and presenting with ALF. Data extracted included clinical and biochemical characteristics, interventions, and outcomes., Results: Three hundred and thirty eligible patients from 61 studies were identified, with an additional five patients from our institution. The majority were female (66.8%), with a median age of 10. Overall, 59.7% achieved native liver survival (NLS), 35% underwent LTx, and 5% died before LTx. The use of corticosteroids with non-steroid immunomodulators increased the likelihood of NLS by 2.5-fold compared to corticosteroids alone. AIH-1 was associated with 3.3-fold odds for NLS, compared to AIH-2. However, on multivariate analysis, only AIH-1 was identified as an independent predictor for NLS (OR 3.8 [95% CI 1.03-14.2], p = .04)., Conclusion: While corticosteroids and non-steroid immunomodulators treatment may offer enhanced probability of achieving NLS, treatment regimens for AIH-ALF may need to consider patient-specific factors, especially AIH type. This highlights the potential for NLS in AIH-ALF and suggest a need to identify biomarkers which predict the need for combination immunosuppression to avoid LTx., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Historically, the therapeutic options available to hepatologists managing cholestasis have been limited. Apart from bile acid--binding resins and the choleretic ursodeoxycholic acid, the medical management of cholestasis in children has been predominately focused on managing the complications of cholestasis, namely pruritus, malnutrition, fat-soluble vitamin deficiencies, and portal hypertension. As such, invasive surgical procedures such as biliary diversion and liver transplantation may become the only options for progressive and unremitting cases of cholestasis. Particularly in the pediatric population, where debilitating pruritus is a common indication for a liver transplant, effective anti-cholestatic medications have the potential to prolong native liver survival without the need for biliary diversion. Ileal bile acid transporter (IBAT) inhibitors are a relatively new class of drugs which that target the ileal re-uptake of bile acids, thus interrupting the enterohepatic circulation and reducing the total bile acid pool size and exposure of the liver. Oral, minimally absorbed IBAT inhibitors have been demonstrated to reduce serum bile acid levels and pruritus with a minimal side effect profile in clinical trials in Alagille Ssyndrome and progressive familial intrahepatic cholestasis, leading to FDA and EMA approval. The indications for IBAT inhibitors will likely expand in the coming years as clinical trials in other adult and pediatric cholestatic conditions are ongoing. This review will summarize the published clinical and pre-clinical data on IBAT inhibitors and offer providers guidance on their practical use., (Copyright © 2024 American Association for the Study of Liver Diseases.)

Background and Aims: Alagille syndrome (ALGS) is characterized by chronic cholestasis with associated pruritus and extrahepatic anomalies. Maralixibat, an ileal bile acid transporter inhibitor, is an approved pharmacologic therapy for cholestatic pruritus in ALGS. Since long-term placebo-controlled studies are not feasible or ethical in children with rare diseases, a novel approach was taken comparing 6-year outcomes from maralixibat trials with an aligned and harmonized natural history cohort from the G lobal AL agille A lliance (GALA) study., Approach and Results: Maralixibat trials comprise 84 patients with ALGS with up to 6 years of treatment. GALA contains retrospective data from 1438 participants. GALA was filtered to align with key maralixibat eligibility criteria, yielding 469 participants. Serum bile acids could not be included in the GALA filtering criteria as these are not routinely performed in clinical practice. Index time was determined through maximum likelihood estimation in an effort to align the disease severity between the two cohorts with the initiation of maralixibat. Event-free survival, defined as the time to first event of manifestations of portal hypertension (variceal bleeding, ascites requiring therapy), surgical biliary diversion, liver transplant, or death, was analyzed by Cox proportional hazards methods. Sensitivity analyses and adjustments for covariates were applied. Age, total bilirubin, gamma-glutamyl transferase, and alanine aminotransferase were balanced between groups with no statistical differences. Event-free survival in the maralixibat cohort was significantly better than the GALA cohort (HR, 0.305; 95% CI, 0.189-0.491; p <0.0001). Multiple sensitivity and subgroup analyses (including serum bile acid availability) showed similar findings., Conclusions: This study demonstrates a novel application of a robust statistical method to evaluate outcomes in long-term intervention studies where placebo comparisons are not feasible, providing wide application for rare diseases. This comparison with real-world natural history data suggests that maralixibat improves event-free survival in patients with ALGS., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Data on oral vancomycin for primary sclerosing cholangitis (PSC)-associated inflammatory bowel disease (IBD) are limited., Aims: Using data from the Paediatric PSC Consortium, to examine the effect of vancomycin on IBD activity., Methods: In this retrospective multi-centre cohort study, we matched vancomycin-treated and untreated patients (1:3) based on IBD duration at the time of primary outcome assessment. The primary outcome was Physician Global Assessment (PGA) of IBD clinical activity after 1 year (±6 months) of vancomycin. We used generalised estimating equations (GEE) to examine the association between vancomycin and PGA remission, adjusting for IBD type, severity and medication exposures. Secondary outcomes included serum labs and endoscopic remission (global rating of no activity) among those with available data and also analysed with GEE., Results: 113 PSC-IBD patients received vancomycin (median age 12.7 years, 63% male). The matched cohort included 70 vancomycin-treated and 210 untreated patients. Vancomycin was associated with greater odds of IBD clinical remission (odds ratio [OR] 3.52, 95% CI 1.97-6.31; adjusted OR [aOR] 5.24, 95% CI 2.68-10.22). Benefit was maintained in sensitivity analyses restricted to non-transplanted patients and those with baseline moderate-severe PGA. Vancomycin was associated with increased odds of endoscopic remission (aOR 2.76, 95% CI 1.002-7.62; N = 101 with data), and with lower CRP (p = 0.03) and higher haemoglobin and albumin (both p < 0.01)., Conclusion: Vancomycin was associated with greater odds of IBD clinical and endoscopic remission. Additional, preferably randomised, controlled studies are needed to characterise efficacy using objective markers of mucosal inflammation, and to examine safety and define optimal dosing., (© 2024 John Wiley & Sons Ltd.)

Background: Ductular reactivity is central to the pathophysiology of cholangiopathies. Mechanisms underlying the reactive phenotype activation by exogenous inflammatory mediators and bile acids are poorly understood., Methods: Using human extrahepatic cholangiocyte organoids (ECOs) we developed an injury model emulating the cholestatic microenvironment with exposure to inflammatory mediators and various pathogenic bile acids. Moreover, we explored roles for the bile acid activated Sphingosine-1-phosphate receptor 2 (S1PR2) and potential beneficial effects of therapeutic bile acids UDCA and norUDCA., Results: Synergistic exposure to bile acids (taurocholic acid, glycocholic acid, glycochenodeoxycholic acid) and TNF-α for 24 hours induced a reactive state as measured by ECO diameter, proliferation, lactate dehydrogenase activity and reactive phenotype markers. While NorUDCA and UDCA treatments given 8 hours after injury induction both suppressed reactive phenotype activation and most injury parameters, proliferation was improved by NorUDCA only. Extrahepatic cholangiocyte organoid stimulation with S1PR2 agonist sphingosine-1-phosphate reproduced the cholangiocyte reactive state and upregulated S1PR2 downstream mediators; these effects were suppressed by S1PR2 antagonist JET-013 (JET), downstream mediator extracellular signal-regulated kinase 1/2 inhibitor, and by norUDCA or UDCA treatments. JET also partially suppressed reactive phenotype after bile acid injury., Conclusions: We developed a novel model to study the reactive cholangiocyte state in response to pathological stimuli in cholestasis and demonstrated a contributory role of S1PR2 signaling in both injury and NorUDCA/UDCA treatments. This model is a valuable tool to further explore the pathophysiology of human cholangiopathies., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Cholestasis is the predominate feature of many pediatric hepatobiliary diseases. The physiologic flow of bile requires multiple complex processes working in concert. Bile acid (BA) synthesis and excretion, the formation and flow of bile, and the enterohepatic reuptake of BAs all function to maintain the circulation of BAs, a key molecule in lipid digestion, metabolic and cellular signaling, and, as discussed in the review, a crucial mediator in the pathogenesis of cholestasis. Disruption of one or several of these steps can result in the accumulation of toxic BAs in bile ducts and hepatocytes leading to inflammation, fibrosis, and, over time, biliary and hepatic cirrhosis. Biliary atresia, progressive familial intrahepatic cholestasis, primary sclerosing cholangitis, and Alagille syndrome are four of the most common pediatric cholestatic conditions. Through understanding the commonalities and differences in these diseases, the important cellular mechanistic underpinnings of cholestasis can be greater appreciated.

Background: Mitochondrial hepatopathies (MHs) are primary mitochondrial genetic disorders that can present as childhood liver disease. No recognized biomarkers discriminate MH from other childhood liver diseases. The protein biomarkers growth differentiation factor 15 (GDF15) and fibroblast growth factor 21 (FGF21) differentiate mitochondrial myopathies from other myopathies. We evaluated these biomarkers to determine if they discriminate MH from other liver diseases in children., Methods: Serum biomarkers were measured in 36 children with MH (17 had a genetic diagnosis); 38 each with biliary atresia, α1-antitrypsin deficiency, and Alagille syndrome; 20 with NASH; and 186 controls., Results: GDF15 levels compared to controls were mildly elevated in patients with α1-antitrypsin deficiency, Alagille syndrome, and biliary atresia-young subgroup, but markedly elevated in MH (p<0.001). FGF21 levels were mildly elevated in NASH and markedly elevated in MH (p<0.001). Both biomarkers were higher in patients with MH with a known genetic cause but were similar in acute and chronic presentations. Both markers had a strong performance to identify MH with a molecular diagnosis with the AUC for GDF15 0.93±0.04 and for FGF21 0.90±0.06. Simultaneous elevation of both markers >98th percentile of controls identified genetically confirmed MH with a sensitivity of 88% and specificity of 96%. In MH, independent predictors of survival without requiring liver transplantation were international normalized ratio and either GDF15 or FGF21 levels, with levels <2000 ng/L predicting survival without liver transplantation (p<0.01)., Conclusions: GDF15 and FGF21 are significantly higher in children with MH compared to other childhood liver diseases and controls and, when combined, were predictive of MH and had prognostic implications., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Background: Our objective was to better understand the natural history and disease modifiers of Alpha-1-antitrypsin deficiency (AATD), a common genetic liver disease causing hepatitis and cirrhosis in adults and children. The clinical course is highly variable. Some infants present with neonatal cholestasis, which can resolve spontaneously or progress to cirrhosis; others are well in infancy, only to develop portal hypertension later in childhood., Methods: The Childhood Liver Disease Research Network has been enrolling AATD participants into longitudinal, observational studies at North American tertiary centers since 2004. We examined the clinical courses of 2 subgroups of participants from the several hundred enrolled; first, those presenting with neonatal cholestasis captured by a unique study, enrolled because of neonatal cholestasis but before specific diagnosis, then followed longitudinally (n=46); second, separately, all participants who progressed to liver transplant (n=119)., Results: We found male predominance for neonatal cholestasis in AATD (65% male, p=0.04), an association of neonatal gamma-glutamyl transpeptidase elevation to more severe disease, and a higher rate of neonatal cholestasis progression to portal hypertension than previously reported (41%) occurring at median age of 5 months. Participants with and without preceding neonatal cholestasis were at risk of progression to transplant. Participants who progressed to liver transplant following neonatal cholestasis were significantly younger at transplant than those without neonatal cholestasis (4.1 vs. 7.8 years, p=0.04, overall range 0.3-17 years). Neonatal cholestasis had a negative impact on growth parameters. Coagulopathy and varices were common before transplant, but gastrointestinal bleeding was not., Conclusions: Patients with AATD and neonatal cholestasis are at risk of early progression to severe liver disease, but the risk of severe disease extends throughout childhood. Careful attention to nutrition and growth is needed., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

The thyroid functions as an apex endocrine organ that controls growth, differentiation and metabolism 1 , and thyroid diseases comprise the most common endocrine disorders 2 . Nevertheless, high-resolution views of the cellular composition and signals that govern the thyroid have been lacking 3,4 . Here, we show that Notch signalling controls homeostasis and thermoregulation in adult mammals through a mitochondria-based mechanism in a subset of thyrocytes. We discover two thyrocyte subtypes in mouse and human thyroids, identified in single-cell analyses by different levels of metabolic activity and Notch signalling. Therapeutic antibody blockade of Notch in adult mice inhibits a thyrocyte-specific transcriptional program and induces thyrocyte defects due to decreased mitochondrial activity and ROS production. Thus, disrupting Notch signalling in adult mice causes hypothyroidism, characterized by reduced levels of circulating thyroid hormone and dysregulation of whole-body thermoregulation. Inducible genetic deletion of Notch1 and 2 in thyrocytes phenocopies this antibody-induced hypothyroidism, establishing a direct role for Notch in adult murine thyrocytes. We confirm that hypothyroidism is enriched in children with Alagille syndrome, a genetic disorder marked by Notch mutations, suggesting that these findings translate to humans., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Background and Aims: Refractory pruritus and other complications of cholestasis are indications for liver transplantation (LT) in patients with Alagille syndrome (ALGS). We evaluated predictors of event-free survival and transplant-free survival in patients with ALGS treated with maralixibat (MRX), an ileal bile acid transporter inhibitor., Approach and Results: We assessed patients with ALGS from 3 clinical trials of MRX with up to 6 years of follow-up. Event-free survival was defined as the absence of LT, surgical biliary diversion, hepatic decompensation, or death; transplant-free survival was the absence of LT or death. Forty-three potential predictors were evaluated, including age, pruritus (ItchRO[Obs] 0-4 scale), biochemistries, platelets, and serum bile acids. Harrell's concordance statistic assessed goodness-of-fit, and then, Cox proportional hazard models confirmed the statistical significance of the predictors identified. A further analysis was performed to identify cutoffs using a grid search. Seventy-six individuals met the criteria of receiving MRX for ≥48 weeks with laboratory values available at week 48 (W48). The median duration of MRX was 4.7 years (IQR: 1.6-5.8); 16 had events (10 LT, 3 decompensation, 2 death, and 1 surgical biliary diversion). The 6-year event-free survival improved with a clinically meaningful >1-point ItchRO(Obs) reduction from baseline to W48 (88% vs. 57%; p = 0.005), W48 bilirubin < 6.5 mg/dL (90% vs. 43%; p < 0.0001), and W48 serum bile acid < 200 µmol/L (85% vs. 49%; p = 0.001). These parameters were also predictive of 6-year transplant-free survival., Conclusions: Improvement in pruritus by 48 weeks, and lower W48 bilirubin and serum bile acid levels were associated with fewer events. These data may help identify potential markers of disease progression for ALGS patients treated with MRX., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Sarcopenia occurs in pediatric chronic liver disease, although the prevalence and contributing factors in genetic intrahepatic cholestasis are not well-described. The objective of this study was to measure muscle mass in school-aged children with genetic intrahepatic cholestasis and assess relationships between sarcopenia, clinical variables, and outcomes., Methods: Estimated skeletal muscle mass (eSMM) was calculated on dual-energy x-ray absorptiometry obtained in a Childhood Liver Disease Research Network study of children with bile acid synthesis disorders(BASD) alpha-1 antitrypsin deficiency (a1ATd), chronic intrahepatic cholestasis (CIC), and Alagille syndrome (ALGS). Relationships between eSMM, liver disease, and transplant-free survival were assessed., Results: eSMM was calculated in 127 participants (5-18 y): 12 BASD, 41 a1ATd, 33 CIC, and 41 ALGS. eSMM z-score was lower in CIC (-1.6 ± 1.3) and ALGS (-2.1 ± 1.0) than BASD (-0.1 ± 1.1) and a1ATd (-0.5 ± 0.8, p < 0.001). Sarcopenia (defined as eSMM z-score ≤- 2) was present in 33.3% of CIC and 41.5% of ALGS participants. eSMM correlated with bone mineral density in the 4 disease groups (r=0.52-0.55, p < 0.001-0.07), but not serum bile acids, bilirubin, aspartate aminotransferase/platelet ratio index, or clinically evident portal hypertension. Of the 2 patients who died (1 with sarcopenia) and 18 who underwent liver transplant (LT, 4 with sarcopenia), eSMM z-score did not predict transplant-free survival. eSMM z-score correlated with the Physical Pediatric Quality of Life Inventory score (r=0.38-0.53, p = 0.007-0.04) in CIC and a1ATd., Conclusion: Severe sarcopenia occurs in some children with ALGS and CIC. The lack of correlation between eSMM and biochemical cholestasis suggests mechanisms beyond cholestasis contribute to sarcopenia. While sarcopenia did not predict transplant-free survival, LT and death were infrequent events. Future studies may define mechanisms of sarcopenia in genetic intrahepatic cholestasis., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Biliary atresia is a fibroinflammatory neonatal disease with no effective therapies. A subset of cases (10-20%) is associated with laterality defects - labeled biliary atresia splenic malformation (BASM) syndrome. Recently, whole-exome sequencing of patients with BASM identified deleterious variants in PKD1L1. PKD1L1 is involved in left-right axis determination; however, its role in cholangiocytes is unknown. We generated the pkd1l1hsc117 allele using CRISPR/Cas9 mutagenesis in zebrafish to determine the role of Pkd1l1 in biliary development and function. Wild-type and mutant larvae were assessed for laterality defects, biliary function and biliary tree architecture at 5 days post fertilization. pkd1l1hsc117 mutant larvae exhibited early left-right patterning defects. The gallbladder was positioned on the left in 47% of mutants compared to 4% of wild-type larvae. Accumulation of PED6 in the gallbladder, an indicator of hepatobiliary function, was significantly reduced in pkd1l1hsc117 mutants (46%) compared to wild-type larvae (4%). pkd1l1hsc117 larvae exhibited fewer biliary epithelial cells and reduced density of the intrahepatic biliary network compared to those in wild-type larvae. These data highlight the essential role of pkd1l1 in normal development and function of the zebrafish biliary system, supporting a role for this gene as a cause of BASM., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

Alagille syndrome (ALGS) is a complex rare genetic disorder that involves multiple organ systems and is historically regarded as a disease of childhood. Since it is inherited in an autosomal dominant manner in 40% of patients, it carries many implications for genetic counselling of patients and screening of family members. In addition, the considerable variable expression and absence of a clear genotype-phenotype correlation, results in a diverse range of clinical manifestations, even in affected individuals within the same family. With recent therapeutic advancements in cholestasis treatment and the improved survival rates with liver transplantation (LT), many patients with ALGS survive into adulthood. Although LT is curative for liver disease secondary to ALGS, complications secondary to extrahepatic involvement remain problematic lifelong. This review is aimed at providing a comprehensive review of ALGS to adult clinicians who will take over the medical care of these patients following transition, with particular focus on certain aspects of the condition that require lifelong surveillance. We also provide a diagnostic framework for adult patients with suspected ALGS and highlight key aspects to consider when determining eligibility for LT in patients with this syndrome., (© 2023. The Author(s).)

Background: We evaluated the proportion, clinical features, and outcomes of previously healthy children presenting to a large Canadian quaternary pediatric center with severe acute hepatitis of unknown etiology., Methods: All patients with serum alanine aminotransferase (ALT) > 500 U/L or aspartate aminotransferase (AST) > 500 U/L between June 1, 2018, and May 31, 2022, at The Hospital for Sick Children, were identified. Subjects with only AST > 500 U/L were excluded. Clinical characteristics, investigations, and outcomes for patients without clear etiology for ALT > 500 U/L (severe acute hepatitis of unknown etiology) for our study period and from October 1 to May 31 of each year 2018-2021 were reviewed., Results: Of 977 patients with ALT/AST> 500 U/L, 720 had only ALT > 500 U/L. We excluded age below 6 months (n = 99) or above 16 years (n = 66), known pre-existing liver conditions (n = 66), and ALT > 500 U/L in already admitted patients (n = 151). Among the remaining 338 children with ALT > 500 U/L at presentation, an etiology was identified in 303 subjects. 33 (9.8%) children [median age 6.1 y (range 0.5-15.5); 61% male] were confirmed as severe acute hepatitis of unknown etiology. Twenty patients (60.6%) were tested for blood adenovirus by PCR, and 1 (5%) was positive (serotype B7). Liver tissue specimens from 18 patients revealed no evidence of viral inclusions or adenovirus. Twelve (36.3%) presented with pediatric acute liver failure, with 8 (24.2%) requiring liver transplantation. There were no deaths. Hepatitis-associated aplastic anemia occurred in 5 (15%) patients., Conclusions: Of children presenting with severe acute hepatitis to a quaternary children's hospital over a 48-month period, 9.8% had unknown etiology with no change over time. Liver transplantation remains an important treatment strategy for those presenting with pediatric acute liver failure phenotype. The frequency of cases associated with human adenovirus infection was noncontributory., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

X-linked myotubular myopathy (XLMTM) is a fatal congenital disorder caused by mutations in the MTM1 gene. Currently, there are no approved treatments, although AAV8-mediated gene transfer therapy has shown promise in animal models and preliminarily in patients. However, 4 patients with XLMTM treated with gene therapy have died from progressive liver failure, and hepatobiliary disease has now been recognized more broadly in association with XLMTM. In an attempt to understand whether loss of MTM1 itself is associated with liver pathology, we have characterized what we believe to be a novel liver phenotype in a zebrafish model of this disease. Specifically, we found that loss-of-function mutations in mtm1 led to severe liver abnormalities including impaired bile flux, structural abnormalities of the bile canaliculus, and improper endosome-mediated trafficking of canalicular transporters. Using a reporter-tagged Mtm1 zebrafish line, we established localization of Mtm1 in the liver in association with Rab11, a marker of recycling endosomes, and canalicular transport proteins and demonstrated that hepatocyte-specific reexpression of Mtm1 could rescue the cholestatic phenotype. Last, we completed a targeted chemical screen and found that Dynasore, a dynamin-2 inhibitor, was able to partially restore bile flow and transporter localization to the canalicular membrane. In summary, we demonstrate, for the first time to our knowledge, liver abnormalities that were directly caused by MTM1 mutation in a preclinical model, thus establishing the critical framework for better understanding and comprehensive treatment of the human disease.

Autoimmune liver diseases are siloed into three syndromes that define clinical practice. These classifiers can, and are, challenged by variant presentations across all ages, something inevitable to disease definitions that rely on interpreting (inherently variable) semi-quantitative/qualitative clinical, laboratory, pathological or radiological findings. Furthermore this categorisation is premised on an ongoing absence of definable disease aetiologies. Clinicians thus encounter individuals with biochemical, serological, and histological manifestations that are common to both primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH), often labelled as 'PSC/AIH-overlap'. In childhood the term 'autoimmune sclerosing cholangitis (ASC)' may be used, and some propose this to be a distinct disease process. In this article we champion the concept that ASC and PSC/AIH-overlap are not distinct entities. Rather, they represent inflammatory phases of PSC frequently manifesting earlier in the disease course, most notably in younger patients. Ultimately, disease outcomes remain similar to those of a more classical PSC phenotype observed in later life. Thus, we argue that it is now time to align disease names and descriptions used by clinicians across all patient subpopulations, to help unify care. This will enhance collaborative studies and ultimately contribute to rational treatment advances., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objectives: To assess abnormal liver enhancement on 15-20 min delayed 3D high-resolution late gadolinium enhancement (3D HR LGE) sequence in patients with Fontan circulation., Methods: Retrospective study of pediatric Fontan patients (< 18 years old) with combined cardiac-liver MRI from January 2018 to August 2021. Abnormal hepatic enhancement was graded (0-3) for each lobe, summed for a total liver enhancement score (0-6), and compared to repaired tetralogy of Fallot (rTOF) patients. Correlations with other hepatic imaging biomarkers were performed. Temporal relationships of enhancement compared to traditional early portal venous and 5-7-min delayed phase liver imaging were analyzed., Results: The Fontan group (n = 35, 13 ± 3.4 years old, median time from Fontan 10 (9-12) years) had 23/35 (66%) with delayed 3D HR LGE total liver enhancement score > 0 (range 0-5), with greater involvement of the right lobe (1 (0-1) vs 0 (0-1), p < 0.01). The rTOF group (n = 35, 14 ± 2.6 years old) had no abnormal enhancement. In the Fontan group, total liver enhancement was 3 (2-4) in the early portal venous phase, lower at 1 (1-2) in the 5-7-min delayed phase (p < 0.01), and lowest at 1 (0-2) in the 15-20-min delayed phase (p = 0.03). 3D HR LGE enhancement correlated inversely with portal vein flow (r s  =  - 0.42, p = 0.01) and positively with left lobe stiffness (r s  = 0.51, p < 0.01). The enhancement score decreased in 13/35 (37%) between the 5-7- and 15-20-min delayed phases., Conclusions: Liver fibrosis can be assessed on 3D HR LGE sequences in patients with Fontan circulation, correlates with other imaging biomarkers of Fontan liver disease, and may add information for hepatic surveillance in this population., Key Points: • Abnormal liver enhancement on 3D HR LGE sequences in Fontan patients likely represents liver fibrosis and is seen in up to 66% of children and adolescents with variable distribution and severity. • The degree of 3D HR LGE liver enhancement correlates with decreased portal vein flow and increased left hepatic lobe stiffness., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

Background: Sarcopenia is associated with adverse outcomes following liver transplantation, and at-risk children must be identified and prehabilitated. The gold standard for assessing sarcopenia in end-stage liver disease (ESLD) is CT assessment of the total Psoas Muscle Area (tPMA). However, radiation exposure and sedation requirements make this approach impractical for children. The bilateral anterior thigh thickness (BATT) is the cumulative measurement of the rectus femoris and vastus intermedius muscles by ultrasound and has been used to identify sarcopenia in adults. There are no studies assessing muscle mass in children using ultrasound. We hypothesized that measuring BATT with ultrasound in children with ESLD is feasible and is associated with sarcopenia., Methods: A prospective pilot feasibility study of patients with ESLD on the liver transplantation waitlist and age-matched healthy controls. BATT was measured by a single operator using ultrasound. tPMA indices were determined by CT imaging, along with clinical and anthropometric data., Results: Thirty children were studied between September 2021 and December 2022, 15 listed patients aged 4-30 months, and 15 controls aged 4-32 months. No major technical challenges or complications were encountered while performing the ultrasounds. Median BATTs of 30.8 mm (interquartile range: 27.9-32.8 mm) versus 32.7 mm (interquartile range: 31.8-36.9 mm) were demonstrated in the ESLD and control groups, respectively, and p = 0.01. A positive correlation (R = 0.603) was demonstrated between BATT and tPMA at the L4-5 level among patients with ESLD. No correlation was observed between BATT and anthropometrics., Conclusions: This study yields novel data on the feasibility of ultrasound to measure mid-thigh thickness in children with ESLD and suggests a correlation between BATT and tPMA, the gold standard for diagnosing sarcopenia. It sets the stage for ultrasound as a simple, noninvasive, and easily repeatable tool for assessing sarcopenia in children., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Background & Aims: PEDFIC 2, an ongoing, open-label, 72-week study, evaluates odevixibat, an ileal bile acid transporter inhibitor, in patients with progressive familial intrahepatic cholestasis., Methods: PEDFIC 2 enrolled and dosed 69 patients across two cohorts; all received odevixibat 120 μg/kg per day. Cohort 1 comprised children from PEDFIC 1, and cohort 2 comprised new patients (any age). We report data through 15 July 2020, with Week 24 of PEDFIC 2 the main time point analysed. This represents up to 48 weeks of cumulative exposure for patients treated with odevixibat from the 24-week PEDFIC 1 study (cohort 1A) and up to 24 weeks of treatment for those who initiated odevixibat in PEDFIC 2 (patients who received placebo in PEDFIC 1 [cohort 1B] or cohort 2 patients). Primary endpoints for this prespecified interim analysis were change from baseline to Weeks 22-24 in serum bile acids (sBAs) and proportion of positive pruritus assessments (≥1-point drop from PEDFIC 2 baseline in pruritus on a 0-4 scale or score ≤1) over the 24-week period. Safety monitoring included evaluating treatment-emergent adverse events (TEAEs)., Results: In cohort 1A, mean change from PEDFIC 1 baseline to Weeks 22-24 of PEDFIC 2 in sBAs was -201 μmol/L ( p <0.0001). For cohort 1B and cohort 2, mean changes from odevixibat initiation to weeks 22-24 in sBAs were -144 and -104 μmol/L, respectively. The proportion of positive pruritus assessments in the first 24-week period of PEDFIC 2 was 33%, 56%, and 62% in cohorts 1A, 1B, and 2, respectively. Most TEAEs were mild or moderate. No drug-related serious TEAEs occurred., Conclusions: Odevixibat in patients with progressive familial intrahepatic cholestasis was generally well tolerated and associated with sustained reductions in sBAs and pruritus., Clinical Trials Registration: This study is registered at ClinicalTrials.gov (NCT03659916)., Impact and Implications: Disrupted bile flow is a hallmark feature of patients with progressive familial intrahepatic cholestasis and can result in build-up of bile constituents in the liver with spill over into the bloodstream; other effects that patients can experience include extremely itchy skin, and because not enough bile reaches the gut, patients can have problems digesting food, which may lead to poor growth. Odevixibat is an orally administered medication that shunts bile acids away from the liver. The current study, called PEDFIC 2, suggested that odevixibat can improve the problematic signs and symptoms of progressive familial intrahepatic cholestasis and was generally safe for patients., Competing Interests: RJT: Albireo and Mirum – Consultant; Generation Bio – Consultant and stock options; Rectify Therapeutics – Consultant and stockholder; LD: Albireo, Alexion, Mirum, Selecta, Vivet, Spark, Tome, and Genespire – Consultant; ADG: Albireo – Consultant; UB: Albireo, Mirum, Alnylam, Vivet, and Nestlé – Consultant; EG: Laboratoires C.T.R.S., Mirum, Vivet, and Albireo – Consultant; TG: Albireo – Consultant; RHJH: GMP-Orphan and Univar – Consultant; BMK: Albireo, Mirum, and Audentes – Consultant; Albireo and Mirum – Unrestricted educational grants; SJK: Albireo, HemoShear, Intercept, Mirum, and Vertex – Consultant; FL: Alexion – Consultant; AL: GMP-Orphan and CSL Behring – Consultant; EL: Mirum – Received honoraria; KML: Albireo, Mirum, and Travere Therapeutics – Consultant; CM: Albireo – Consultant; PM: Sobi AB and Albireo – Consultant; EtSo: Cellaion – Chairman and CEO; Albireo – Consultant and investigator; Mirum and Intercept – Investigator; RJS: Mirum, Albireo, and Alexion – Consultant; EkSt: Albireo and Mirum – Consultant and research support; Univar – Consultant; Orphalan – Speaker's fee; HJV: Ausnutria BV, Albireo, Danone/Nutricia Research, Intercept, Mirum, Orphalan, and Vivet – Consultant; JMV: Mirum – Consultant; JPM, QN, TW, NW, QY, PH, and LK: Albireo – current or former employment; RA, PLC, PC, BD, ÖD, GG, WH, HÖ, SRR, BR, EySh, NS, MET, and WLvdW: nothing to disclose. Please refer to the accompanying ICMJE disclosure forms for further details., (© 2023 The Authors.)

Background and Aims: Alagille syndrome (ALGS) is a multisystem disorder, characterized by cholestasis. Existing outcome data are largely derived from tertiary centers, and real-world data are lacking. This study aimed to elucidate the natural history of liver disease in a contemporary, international cohort of children with ALGS., Approach and Results: This was a multicenter retrospective study of children with a clinically and/or genetically confirmed ALGS diagnosis, born between January 1997 and August 2019. Native liver survival (NLS) and event-free survival rates were assessed. Cox models were constructed to identify early biochemical predictors of clinically evident portal hypertension (CEPH) and NLS. In total, 1433 children (57% male) from 67 centers in 29 countries were included. The 10 and 18-year NLS rates were 54.4% and 40.3%. By 10 and 18 years, 51.5% and 66.0% of children with ALGS experienced ≥1 adverse liver-related event (CEPH, transplant, or death). Children (>6 and ≤12 months) with median total bilirubin (TB) levels between ≥5.0 and <10.0 mg/dl had a 4.1-fold (95% confidence interval [CI], 1.6-10.8), and those ≥10.0 mg/dl had an 8.0-fold (95% CI, 3.4-18.4) increased risk of developing CEPH compared with those <5.0 mg/dl. Median TB levels between ≥5.0 and <10.0 mg/dl and >10.0 mg/dl were associated with a 4.8 (95% CI, 2.4-9.7) and 15.6 (95% CI, 8.7-28.2) increased risk of transplantation relative to <5.0 mg/dl. Median TB <5.0 mg/dl were associated with higher NLS rates relative to ≥5.0 mg/dl, with 79% reaching adulthood with native liver ( p < 0.001)., Conclusions: In this large international cohort of ALGS, only 40.3% of children reach adulthood with their native liver. A TB <5.0 mg/dl between 6 and 12 months of age is associated with better hepatic outcomes. These thresholds provide clinicians with an objective tool to assist with clinical decision-making and in the evaluation of therapies., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of American Association for the Study of Liver Diseases.)

Background and Aims: Detailed investigation of the biological pathways leading to hepatic fibrosis and identification of liver fibrosis biomarkers may facilitate early interventions for pediatric cholestasis., Approach and Results: A targeted enzyme-linked immunosorbent assay-based panel of nine biomarkers (lysyl oxidase, tissue inhibitor matrix metalloproteinase (MMP) 1, connective tissue growth factor [CTGF], IL-8, endoglin, periostin, Mac-2-binding protein, MMP-3, and MMP-7) was examined in children with biliary atresia (BA; n = 187), alpha-1 antitrypsin deficiency (A1AT; n = 78), and Alagille syndrome (ALGS; n = 65) and correlated with liver stiffness (LSM) and biochemical measures of liver disease. Median age and LSM were 9 years and 9.5 kPa. After adjusting for covariates, there were positive correlations among LSM and endoglin ( p = 0.04) and IL-8 ( p < 0.001) and MMP-7 ( p < 0.001) in participants with BA. The best prediction model for LSM in BA using clinical and lab measurements had an R2 = 0.437; adding IL-8 and MMP-7 improved R2 to 0.523 and 0.526 (both p < 0.0001). In participants with A1AT, CTGF and LSM were negatively correlated ( p = 0.004); adding CTGF to an LSM prediction model improved R2 from 0.524 to 0.577 ( p = 0.0033). Biomarkers did not correlate with LSM in ALGS. A significant number of biomarker/lab correlations were found in participants with BA but not those with A1AT or ALGS., Conclusions: Endoglin, IL-8, and MMP-7 significantly correlate with increased LSM in children with BA, whereas CTGF inversely correlates with LSM in participants with A1AT; these biomarkers appear to enhance prediction of LSM beyond clinical tests. Future disease-specific investigations of change in these biomarkers over time and as predictors of clinical outcomes will be important., (Copyright © 2023 American Association for the Study of Liver Diseases.)

Background: Biliary atresia (BA) is one of the causes of conjugated hyperbilirubinemia in infants which if untreated leads to end-stage liver disease and death. Percutaneous Trans-hepatic Cholecysto-Cholangiography (PTCC) is a minimally invasive study which can be utilized in the diagnostic work-up of these patients. This study's purpose is to describe the experience with PTCC in neonates, the imaging findings encountered, and the abnormal patterns which warrant further investigation., Methods: A 16-year single-center retrospective study of patients with persistent neonatal cholestasis (suspected BA) undergoing PTCC. Patient demographics, laboratory values, PTCC images, pathology and surgical reports were reviewed., Results: 73 patients underwent PTCC (68% male, mean age 8.7 weeks, mean weight 4.0 Kg). The majority of studies were normal (55%). Abnormal patterns were identified in 33 cases, 79% were diagnosed with BA and 12% with Alagille syndrome. Non-opacification of the common hepatic duct with a narrowed common bile duct (42%) and isolated small gallbladder (38%) were the most common patterns in BA., Conclusion: PTCC is a minimally invasive study in the diagnostic work-up of infants presenting with conjugated hyperbilirubinemia (suspected BA). Further invasive investigations or surgery can be avoided when results are normal., (© 2022. The Author(s).)

Objective: The objective of this study was to assess the impact of treatment response to the ileal bile acid transporter inhibitor maralixibat on health-related quality of life (HRQoL) in children with Alagille syndrome., Study Design: This analysis used data from the ICONIC trial, a phase 2 study with a 4-week double-blind, placebo-controlled, randomized drug withdrawal period in children with Alagille syndrome with moderate-to-severe pruritus. Clinically meaningful treatment response to maralixibat was defined a priori as a ≥1-point reduction in the Itch-Reported Outcome (Observer) score, from baseline to week 48. HRQoL was assessed using the Pediatric Quality of Life Inventory Generic Core, Family Impact, and Multidimensional Fatigue scale scores, which were collected via the caregiver. The minimal clinically important difference for HRQoL ranged from 4 to 5 points, depending on the scale., Results: Twenty of the 27 patients (74%) included in this analysis achieved an Itch-Reported Outcome (Observer) treatment response at week 48. The mean (SD) change in Multidimensional Fatigue score was +25.8 (23.0) for responders vs -3.1 (19.8) for nonresponders (P = .03). Smaller and non-statistically significant mean changes were observed for the Pediatric Quality of Life Inventory Generic Core and Family Impact scores. Controlling for baseline Family Impact score, responders' Family Impact scores increased an average of 16.9 points over 48 weeks compared with non-responders (P = .05). Smaller and non-statistically significant point estimates were observed for the Pediatric Quality of Life Inventory Generic Core and Multidimensional Fatigue scores., Conclusion: The significant improvements in pruritus seen with maralixibat at week 48 of the ICONIC study are clinically meaningful and are associated with improved HRQoL., Trial Registration: ClinicalTrials.gov: NCT02160782., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

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., Competing Interests: Antonia Felzen [MD/PhD scholarship University of Groningen], Daan B.E. van Wessel [MD/PhD scholarship University of Groningen], Emmanuel M. Gonzales [Consultant for CTRS, Vivet Therapeutics, Mirum Pharmaceuticals and Albireo], Richard J. Thompson [Consultant for Shire, Albireo, Mirum Pharmaceuticals, Horizon Pharmaceuticals, Sana Biotechnology, GenerationBio, Retrophin and Qing Bile Therapeutics], Irena Jankowska [Nothing to disclose], Benjamin L. Shneider [Nothing to disclose], Etienne Sokal [Founder, board director and Chairman of the Scientific & Medical advisor board of Promethera Biosciences; consultant Johnson&Johnson], Tassos Grammatikopoulos [Consultant for Albireo], Agustina Kadaristiana [Nothing to disclose], Emmanuel Jacquemin [Consultant for CTRS and Vivet Therapeutics], Anne Spraul [Nothing to disclose], Patryk Lipiński [Nothing to disclose], Piotr Czubkowski [Nothing to disclose], Nathalie Rock [Nothing to disclose], Mohammad Shagrani [Nothing to disclose], Dieter Broering [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], Bjorn Fischler [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 and Orphalan pharmaceuticals], Florence Lacaille [Nothing to disclose], Cristina Goncalves [Nothing to disclose], Loreto Hierro [Nothing to disclose], Gema Munoz Bartolo [Nothing to disclose], Yael Mozer- Glassberg [Nothing to disclose], Amer Azaz [Nothing to disclose], Jernej Brecelj [Nothing to disclose], Antal Dezsofi [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], Nanda Kerkar [Nothing to disclose], Marianne Hørby Jørgensen [Nothing to disclose], Ryan Fischer [Consultant for Albireo and Mirum Pharmaceuticals], Carolina Jimenez-Rivera [Nothing to disclose], Seema Alam [Nothing to disclose], Mara Cananzi [Attended one advisory board meeting with Albireo, Mirum Pharmaceuticals and Nestlè; consultant for CTRS], Noemie Laverdure [Consultant for Abbvie], Cristina Targa Ferreira [Nothing to disclose], Felipe Ordoñez Guerrero [Nothing to disclose], Heng Wang [Nothing to disclose], Valerie Sency [Nothing to disclose], Kyungmo Kim [Nothing to disclose], Huey-Ling Chen [Nothing to disclose], Elisa de Carvalho [Nothing to disclose], Alexandre Fabre [Nothing to disclose], Jesus Quintero Bernabeu [Nothing to disclose], Aglaia Zellos [Nothing to disclose], Estella M. Alonso [Nothing to disclose], Ronald J. Sokol [Consultant for Albireo and Mirum Pharmaceuticals], Frederick J. Suchy [Nothing to disclose], Kathleen M. Loomes [Consultant for Albireo, Mirum and Travere Therapeutics], Patrick J. McKiernan [Consultant for Albireo], Philip Rosenthal [Grant/Research Support by Gilead, AbbVie, Merck, Albireo, Mirum Pharmaceuticals, Arrowhead and Travere; consultant for Gilead, AbbVie, Audentes, Dicerna, Albireo, Mirum Pharmaceuticals, Travere, Takeda, Encoded, BioMarin, MedinCell and Ambys], Yumirle Turmelle [Nothing to disclose], Simon Horslen [Grant/Research support from Mirum Pharmaceuticals], Kathleen Schwarz [Grant support from Gilead, Albireo and the Global Alagille Syndrome Alliance; consultant for Mirum Pharmaceuticals, Up to Date and Sarepta], Jorge A. Bezerra [Grant support from Gilead and Albireo], Kasper Wang [Nothing to disclose], Bettina Hansen [Unrestricted grant support from Cymabay, Intercept, Calliditas, Mirum Pharmaceuticals and Albireo; consultant for Mirum Pharmaceuticals, Albireo AB, Chemomab, Calliditas, Intercept, Cyma Bay,], Henkjan J. Verkade [Consultant for Danone/Nutricia Research, Ausnutria BV, Albireo AB, Mirum Parmaceuticals, Intercept and Vivet]. Please refer to the accompanying ICMJE disclosure forms for further details., (© 2022 The Author(s).)

Background and Aims: Wilson disease (WD) has diverse presentations that frequently mimic other liver diseases. Distinguishing WD from non-alcoholic fatty liver disease (NAFLD) and autoimmune hepatitis (AIH), can be difficult and has critical implications for medical management. This study aimed to examine the utility of histological features of WD in children compared to those with NAFLD and AIH., Methods: A review of liver biopsy slides was performed in children with a clinical and/or genetic diagnosis of WD, seen at the Hospital for Sick Children between 1981 and 2019 and compared to controls with NAFLD and AIH. 37 children with WD and 37 disease controls (20 NAFLD; 17 AIH) were included. Three pathologists, blind to clinical details and diagnosis, reviewed all liver biopsies to reach consensus. Clinical and histopathologic features were compared between groups., Results: Most WD cases displayed steatosis or steatohepatitis on histology (34/37), active AIH-pattern in 1 and inactive cirrhosis in 2 cases. Electron microscopy (EM) findings of mitochondrial abnormalities including dilated tips of cristae, pleomorphism, membrane duplication and dense matrix were more frequent in the WD group as compared to disease controls (p < 0.0001). In WD, dilated tips of mitochondrial cristae had a sensitivity of 91% and specificity of 86%, best among EM features., Conclusions: Light microscopic findings display considerable overlap among children with WD, NAFLD and AIH. Ultrastructural findings of mitochondrial abnormalities are important to distinguish WD from NAFLD and AIH. EM examination should be considered essential in the diagnostic work-up of paediatric liver biopsies., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

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.)

Alagille syndrome (ALGS) is a complex heterogenous disease with a wide array of clinical manifestations in association with cholestatic liver disease. Major clinical and genetic advancements have taken place since its first description in 1969. However, clinicians continue to face considerable challenges in the management of ALGS, particularly in the absence of targeted molecular therapies. In this article, we provide an overview of the broad ALGS phenotype, current approaches to diagnosis and with particular focus on key clinical challenges encountered in the management of these patients., Competing Interests: Disclosure B.M. Kamath is a Consultant for Mirum, Albireo, Audentes and Third Rock Ventures. The author receives unrestricted educational grant funding from Mirum and Albireo. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the article, or in the decision to publish the results. M.D. Ayoub has nothing to disclose., (Copyright © 2022 Elsevier Inc. All rights reserved.)

There is growing interest in, but limited data about, intestinal bile acid transport inhibitors as treatment for cholestatic liver disease. The current analyses combine two similar randomized placebo-controlled trials with subsequent extension phases investigating the impact of maralixibat in children with severe cholestasis secondary to Alagille Syndrome (n = 57). The primary outcomes were measures of pruritus (ItchRO[Obs]) and clinician scratch scale (CSS), both increasing in severity from 0 to 4) and quality of life (QoL) (Parent PedsQL and Multidimensional Fatigue Scale module [MFS] scaled 0-100 with increased QoL) at week 48 of the extension phase relative to the baseline of the placebo-controlled trials (week 13). Secondary assessments included other clinical and biochemical parameters assessed in participants at week 72 or end of treatment (after week 48). At week 48, statistically and clinically significant least square mean (95% CI) improvements in pruritus and QoL were observed (ItchRO[Obs] -1.59 [-1.81, -1.36], CSS -1.36 [-1.67, -1.05], PedsQL +10.17 [4.48, 15.86], and multidimension fatigue [MFS] +13.97 [7.85, 20.08]). At week 48, serum bile acids, platelet count, and cholesterol decreased, whereas alanine aminotransferase (ALT) increased and total bilirubin (TB) and albumin were stable. Changes were durable at week 72 and end of treatment. There were no deaths; 2 participants underwent liver transplantation. Study drug was discontinued in 9 participants after treatment-emergent adverse events, 6 of which were events of increased ALT or TB. Conclusion: Maralixibat administration was associated with marked improvement in pruritus and QoL. Interpretation of these findings is complicated by the complex natural history of severe cholestasis in Alagille syndrome., (© 2022 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)

Malnutrition in children with chronic cholestasis is a prevalent issue and a major risk factor for adverse outcomes. Fat soluble vitamin (FSV) deficiency is an integral feature of cholestatic disease in children, often occurring within the first months of life in those with neonatal cholestasis and malnutrition. This review focuses on FSVs in cholestasis, with particular emphasis on a practical approach to surveillance and supplementation that includes approaches that account for differing local resources. The overarching strategy suggested is to incorporate recognition of FSV deficiencies in cholestatic children in order to develop practical plans for close monitoring and aggressive FSV repletion. Routine attention to FSV assessment and supplementation in cholestatic infants will reduce long periods of inadequate levels and subsequent adverse clinical sequalae., Competing Interests: Disclosure B.M. Kamath: Mirum (Consultant, Unrestricted Educational Grant); Albireo (Consultant, Unrestricted Educational Grant); Astellas, Third Rock Ventures. S.J. Karpen: Consultant for Albireo, Intercept, Mirum, Vertex. S.S. Sundaram: Consultant for Mirum. R.J. Sokol: Consultant for Albireo, Mirum, Alexion., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The conduct of long-term conventional randomized clinical trials in rare diseases is very difficult, making evidenced-based drug development problematic. As a result, real-world data/evidence are being used more frequently to assess new therapeutic approaches in orphan diseases. In this investigation, inclusion and exclusion criteria from a published trial of maralixibat in Alagille syndrome (ALGS, ITCH NCT02057692) were applied to a prospective longitudinal cohort of children with cholestasis (LOGIC NCT00571272) to derive contextual comparator data for evolving clinical trials of intestinal bile acid transport inhibitors in ALGS. A natural history/clinical care cohort of 59 participants who met adapted inclusion and exclusion criteria of ITCH was identified from 252 LOGIC participants with ALGS with their native liver. Frequency weighting was used to match the age distribution of ITCH and yielded a cohort (Alagille Syndrome Natural History [ALGS NH]) that was very similar to the baseline status of ITCH participants. During a 2-year prospective follow-up there was a significant reduction in pruritus in the weighted ALGS NH cohort as assessed by the clinician scratch score (-1.43 [0.28] -1.99, -0.87; mean [SEM] 95% confidence interval). During the same time period, the total bilirubin, albumin, and alanine aminotransferase levels were unchanged, whereas platelet count dropped significantly (-65.2 [16.2] -98.3, -32.1). Weighted survival with native liver was 91% at 2 years in the ALGS NH. These investigations provide valuable real-world data that can serve as contextual comparators to current clinical trials, especially those without control populations, and highlight the value and importance of funded multicenter, prospective, natural history studies., (© 2022 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)

With the application of modern investigative technologies, cholestatic liver diseases of genetic etiology are increasingly identified as the root cause of previously designated "idiopathic" adult and pediatric liver diseases. Here, we review advances in the field enhanced by a deeper understanding of the phenotypes associated with specific gene defects that lead to cholestatic liver diseases. There are evolving areas for clinicians in the current era specifically regarding the role for biopsy and opportunities for a "sequencing first" approach. Risk stratification based on the severity of the genetic defect holds promise to guide the decision to pursue primary liver transplantation versus medical therapy or nontransplant surgery, as well as early screening for HCC. In the present era, the expanding toolbox of recently approved therapies for hepatologists has real potential to help many of our patients with genetic causes of cholestasis. In addition, there are promising agents under study in the pipeline. Relevant to the current era, there are still gaps in knowledge of causation and pathogenesis and lack of fully accepted biomarkers of disease progression and pruritus. We discuss strategies to overcome the challenges of genotype-phenotype correlation and draw attention to the extrahepatic manifestations of these diseases. Finally, with attention to identifying causes and treatments of genetic cholestatic disorders, we anticipate a vibrant future of this dynamic field which builds upon current and future therapies, real-world evaluations of individual and combined therapeutics, and the potential incorporation of effective gene editing and gene additive technologies., (© 2022 American Association for the Study of Liver Diseases.)

Neonatal hemochromatosis is a rare condition that causes neonatal liver failure, frequently resulting in fetal loss or neonatal death. It is thought that most cases of neonatal hemochromatosis are caused by gestational alloimmune liver disease (GALD), with neonatal hemochromatosis being a phenotype of GALD rather than a disease process. Extrahepatic siderosis in the pancreas, myocardium, thyroid and minor salivary gland is a characteristic feature of neonatal hemochromatosis. There is also sparing of the reticuloendothelial system with no iron deposition in the spleen. Hepatic and extrahepatic siderosis seen in neonatal hemochromatosis is from iron dysregulation secondary to liver damage rather than iron deposition causing the liver damage. The presence of extrahepatic siderosis in the pancreas and thyroid is diagnostic of neonatal hemochromatosis and can be detected noninvasively by multi-echo gradient recalled echo (GRE) T2*-weighted sequence of MRI within hours of birth. This helps to expedite the treatment in the form of intravenous immunoglobulin and exchange transfusion, which improves the survival in these babies. The finding of hepatic siderosis is nonspecific and does not help in the diagnosis of neonatal hemochromatosis because it is seen with other causes of advanced liver disease., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

X-linked myotubular myopathy (XLMTM) is a rare, life-threatening congenital myopathy characterized by profound skeletal muscle weakness, respiratory distress, and motor dysfunction. However, pathology is not limited to muscle and can be associated with life-threatening hepatic peliosis. Hepatobiliary disease has been reported in up to 17% of XLMTM patients but has not been extensively characterized. We report on five XLMTM patients who experienced intrahepatic cholestasis in their disease natural history, illustrating the need to further investigate these manifestations. These patients shared presentations that included pruritus, hypertransaminemia, and hyperbilirubinemia with normal gamma-glutamyl transferase, following infection or vaccination. Three patients who had genetic testing showed no evidence of genetic mutations associated with familial cholestasis. In one patient, progression to cirrhotic, decompensated liver disease occurred. Further investigations into the molecular pathomechanism underpinning these clinical observations in XLMTM patients will be important for informing patient care.

Objective: To evaluate neurodevelopmental status among children with inherited cholestatic liver diseases with native liver and variables predictive of impairment., Methods: Participants with Alagille syndrome (ALGS), progressive familial intrahepatic cholestasis (PFIC), and alpha 1 antitrypsin deficiency (A1AT) enrolled in a longitudinal, multicenter study and completed the Wechsler Preschool and Primary Scale of Intelligence-III or Intelligence Scale for Children-IV. Full Scale Intelligence Quotient (FSIQ) was analyzed continuously and categorically (>100, 85-99, 70-84, <70). Univariate linear regression was performed to study association between FSIQ and risk factors, stratified by disease., Results: Two hundred and fifteen completed testing (ALGS n = 70, PFIC n = 43, A1AT n = 102); median age was 7.6 years (3.0-16.9). Mean FSIQ in ALGS was lower than A1AT (94 vs 101, P = 0.01). Frequency of FSIQ < 85 (>1 standard deviation [SD] below average) was highest in ALGS (29%) versus 18.6% in PFIC and 12.8% in A1AT, and was greater than expected in ALGS based on normal distribution (29% vs 15.9%, P = 0.003). ALGS scored significantly lower than test norms in almost all Wechsler composites; A1AT scored lower on Working Memory and Processing Speed; PFIC was not different from test norms. Total bilirubin, alkaline phosphatase, albumin, hemoglobin, and parental education were significantly associated with FSIQ., Conclusions: Patients with ALGS are at increased risk of lower FSIQ, whereas our data suggest A1AT and PFIC are not. A1AT and ALGS appear vulnerable to working memory and processing speed deficits suggestive of attention/executive function impairment. Malnutrition, liver disease severity, and sociodemographic factors appear related to FSIQ deficits, potentially identifying targets for early interventions., Competing Interests: Conflicts of Interest: D.H.L. reports grant/research support from Abbvie, Gilead, and CF Foundation; he also serves on advisory panels for Merck and Gilead. B.M.K. is a consultant for Mirum, Albireo and Audentes; she has unrestricted educational grants from Mirum and Albireo. V.L.N. is a consultant for Albireo. P.R. reports grants from Gilead, Merck, BMS, AbbVie, Travere Therapeutics, Albireo, and Mirum, Arrowhead; and serving as a consultant for Gilead, Mirum, Albireo, Audentes, and Vertex. R.J.S. reports consulting for Albireo, Mirum/Shire, and Retrophin (all <$10,000 per year). K.M.L. reports consulting for Albireo, Mirum and Retrophin (now known as Travere Therapeutics). The remaining authors report no conflicts of interest. The study sponsors did not have a role in study design; collection, analysis, and interpretation of data; writing of the report; or the decision to submit the paper for publication., (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: Recurrent primary sclerosing cholangitis (rPSC) following liver transplant (LT) has a negative impact on graft and patient survival; little is known about risk factors for rPSC or disease course in children., Approach and Results: We retrospectively evaluated risk factors for rPSC in 140 children from the Pediatric PSC Consortium, a multicenter international registry. Recipients underwent LT for PSC and had >90 days of follow-up. The primary outcome, rPSC, was defined using Graziadei criteria. Median follow-up after LT was 3 years (interquartile range 1.1-6.1). rPSC occurred in 36 children, representing 10% and 27% of the subjects at 2 years and 5 years following LT, respectively. Subjects with rPSC were younger at LT (12.9 vs. 16.2 years), had faster progression from PSC diagnosis to LT (2.5 vs. 4.1 years), and had higher alanine aminotransferase (112 vs. 66 IU/L) at LT (all P < 0.01). Inflammatory bowel disease was more prevalent in the rPSC group (86% vs. 66%; P = 0.025). After LT, rPSC subjects had more episodes of biopsy-proved acute rejection (mean 3 vs. 1; P < 0.001), and higher prevalence of steroid-refractory rejection (41% vs. 20%; P = 0.04). In those with rPSC, 43% developed complications of portal hypertension, were relisted for LT, or died within 2 years of the diagnosis. Mortality was higher in the rPSC group (11.1% vs. 2.9%; P = 0.05)., Conclusions: The incidence of rPSC in this cohort was higher than previously reported, and was associated with increased morbidity and mortality. Patients with rPSC appeared to have a more aggressive, immune-reactive phenotype. These findings underscore the need to understand the immune mechanisms of rPSC, to lay the foundation for developing new therapies and improve outcomes in this challenging population., (© 2021 by the American Association for the Study of Liver Diseases.)

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.)