Alagille syndrome and liver transplantation

UK guideline on the transition and management of childhood liver diseases in adulthood

INTRODUCTION

Improved outcomes of liver disease in childhood and young adulthood have resulted in an increasing number of young adults (YA) entering adult liver services. The adult hepatologist therefore requires a working knowledge in diseases that arise almost exclusively in children and their complications in adulthood.

AIMS

To provide adult hepatologists with succinct guidelines on aspects of transitional care in YA relevant to key disease aetiologies encountered in clinical practice.

METHODS

A systematic literature search was undertaken using the Pubmed, Medline, Web of Knowledge and Cochrane database from 1980 to 2023. MeSH search terms relating to liver diseases ('cholestatic liver diseases', 'biliary atresia', 'metabolic', 'paediatric liver diseases', 'autoimmune liver diseases'), transition to adult care ('transition services', 'young adult services') and adolescent care were used. The quality of evidence and the grading of recommendations were appraised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.

RESULTS

These guidelines deal with the transition of YA and address key aetiologies for the adult hepatologist under the following headings: (1) Models and provision of care; (2) screening and management of mental health disorders; (3) aetiologies; (4) timing and role of liver transplantation; and (5) sexual health and fertility.

CONCLUSIONS

These are the first nationally developed guidelines on the transition and management of childhood liver diseases in adulthood. They provide a framework upon which to base clinical care, which we envisage will lead to improved outcomes for YA with chronic liver disease.

Hepatoblastoma in a cirrhotic child with Alagille syndrome

Alagille syndrome (AGS) is a genetic disorder due to mutations in the JAGGED 1 or NOTCH 2 genes leading to multisystemic manifestations. Though these patients are at risk of developing various liver tumours, no cases of hepatoblastoma among young children with cirrhosis in AGS have been reported. We report a male toddler, with cirrhosis due to AGS who developed a hepatoblastoma. He underwent a liver transplant for decompensated chronic liver disease with marked pruritus, very high alpha-fetoprotein levels and malignant liver lesions on positron emission tomography CT. His explant histology revealed a paucity of bile ducts and liver lesions turned out to be hepatoblastoma for which he received postoperative chemotherapy. The genetic testing sent before transplantation confirmed the clinical diagnosis of AGS. Hepatoblastoma should be suspected in any child with AGS presenting with a right upper quadrant mass even in the setting of chronic liver disease.

Alagille syndrome: understanding the genotype-phenotype relationship and its potential therapeutic impact

INTRODUCTION

Alagille syndrome (ALGS) is an autosomal dominant, multisystem genetic disorder with wide phenotypic variability caused by mutations in the Notch signaling pathway, specifically from mutations in either the Jagged1 (JAG1) or NOTCH2 gene. The range of clinical features in ALGS can involve various organ systems including the liver, heart, eyes, skeleton, kidney, and vasculature. Despite the genetic mutations being well-defined, there is variable expressivity and individuals with the same mutation may have different clinical phenotypes.

AREAS COVERED

While no clear genotype-phenotype correlation has been identified in ALGS, this review will summarize what is currently known about the genotype-phenotype relationship and how this relationship influences the treatment of the multisystemic disorder. This review includes discussion of numerous studies which have focused on describing the genotype-phenotype relationship of different organ systems in ALGS as well as relevant basic science and population studies of ALGS. A thorough literature search was completed via the PubMed and National Library of Medicine GeneReviews databases including dates from 1969, when ALGS was first identified, to February 2023.

EXPERT OPINION

The genetics of ALGS are well defined; however, ongoing investigation to identify genotype-phenotype relationships as well as genetic modifiers as potential therapeutic targets is needed. Clinicians and patients alike would benefit from identification of a correlation to aid in diagnostic evaluation and management.

Maralixibat is an alternative to liver transplantation in children with Alagille syndrome

Alagille syndrome is a genetic multisystem disease in which one of the key symptoms that significantly impairs quality of life is cholestatic pruritus. Until recently the only treatment opportunity was liver transplantation. In 2021 the new drug maralixibat (Marixibat) was approved and registered in the United States. This article presents the first experience of using this medication in Russia. The patient stopped itching, significantly reduced the serum bile acids and also improved physical development within 7 months of therapy. Our first experience of using maralixibat in Russia, as well as the available literature data indicates a significant improvement in the quality of life of patients and allows us to consider this drug as an alternative to liver transplantation.

Impact of liver dysfunction on outcomes in children with Alagille syndrome undergoing congenital heart surgery

OBJECTIVES

Children with Alagille syndrome often have complex forms of congenital heart defects with the majority having peripheral pulmonary artery stenosis (PPAS) and pulmonary valve atresia (PA) or pulmonary valve stenosis. Children with Alagille syndrome also have variable amounts of liver dysfunction. The purpose of this study was to evaluate the impact of liver dysfunction on outcomes in children with Alagille syndrome undergoing congenital heart surgery.

METHODS

This was a retrospective review of 69 patients with Alagille syndrome who underwent congenital heart surgery at our institution. The underlying diagnoses included PPAS (n = 29), tetralogy of Fallot with PPAS (n = 14), tetralogy with PA (n = 3), PA with ventricular septal defect and major aortopulmonary collateral arteries (n = 21) and one each with D-transposition and supravalvar aortic stenosis.

RESULTS

The median age at surgery was 16 months (range 0-228 months). Procedures performed included PPAS repair (n = 43), tetralogy with PA repair (n = 3), unifocalization procedures (n = 21) and other (n = 2). Forty-two (61%) patients had mild or no liver dysfunction, while 26 (38%) had moderate or severe liver dysfunction. The median cardiopulmonary bypass time was 345 min (341 with liver dysfunction, 345 without liver dysfunction). There were a total of 8 operative (12%) deaths and 3 late (4%) deaths. Six operative and 2 late deaths occurred in patients with liver dysfunction (combined 30.7%) versus 2 operative and 1 late death (combined 7.1%) for patients without liver dysfunction (P < 0.05).

CONCLUSIONS

These results suggest that liver dysfunction has a profound impact on survival in children with Alagille syndrome undergoing congenital heart surgery.

Pediatric Liver Transplant Survival in Alagille Syndrome Is Comparable to Biliary Atresia-A Linked Database Analysis

OBJECTIVES

This study aims to report liver transplantation (LT) outcomes and cardiac disease manifestations in children with Alagille Syndrome (ALGS) in a contemporary cohort.

METHODS

This project used a novel linkage between the Scientific Registry of Transplant Recipients and Pediatric Health Information System databases. All children ≤21 years undergoing a first LT were identified (2002-2018). The presence of ALGS was identified using Scientific Registry of Transplant Recipients diagnosis coding. Subjects with ALGS were age-matched 1:2 to LT recipients with biliary atresia (BA). The Kaplan-Meier method and log-rank test were used to compare patient and graft survival between groups.

RESULTS

A total of 156 LT recipients with ALGS were identified and matched to a control group of 312 LT recipients with BA. Children with ALGS were more likely to have an associated diagnosis of congenital heart disease (80.7% vs 16.4%; P = 0.001) compared with children with BA with 40 (25.6%) children with AGS requiring cardiac intervention (catheter or surgical) either before or after LT. Those patients with ALGS had a higher creatinine, laboratory MELD, and PELD scores before LT. No difference was observed regarding patient or graft survival between children with ALGS and children with BA ( P = 0.08 and P = 0.27, respectively).

CONCLUSIONS

Despite increased rate of congenital heart defects and cardiac interventions, higher creatinine, and higher laboratory MELD/PELD scores at time of transplant, this study demonstrates that there is no difference in either patient or graft survival between patients with ALGS and BA.

Alagille Syndrome: A Focused Review on Clinical Features, Genetics, and Treatment

Alagille syndrome (ALGS) is an autosomal dominant disorder caused by pathogenic variants in JAG1 or NOTCH2, which encode fundamental components of the Notch signaling pathway. Clinical features span multiple organ systems including hepatic, cardiac, vascular, renal, skeletal, craniofacial, and ocular, and occur with variable phenotypic penetrance. Genotype-phenotype correlation studies have not yet shown associations between mutation type and clinical manifestations or severity, and it has been hypothesized that modifier genes may modulate the effects of JAG1 and NOTCH2 pathogenic variants. Medical management is supportive, focusing on clinical manifestations of disease, with liver transplant indicated for severe pruritus, liver synthetic dysfunction, portal hypertension, bone fractures, and/or growth failure. New therapeutic approaches are under investigation, including ileal bile acid transporter (IBAT) inhibitors and other approaches that may involve targeted interventions to augment the Notch signaling pathway in involved tissues.

Kidney disease in children with heart or liver transplant

Over the past few decades, there has been increasing recognition of kidney disease in children with non-kidney solid organ transplantation. The risk of kidney disease in children undergoing heart or liver transplantation is higher than the general population as the underlying disease and its associated management may directly impair kidney function. Both heart and liver failures contribute to hypoperfusion and kidney ischemia before patients reach the point of transplant. The transplant surgery itself can often be complicated by acute kidney injury (AKI), which may be further exacerbated by a complicated postoperative course. In the short- and long-term post-transplant period, these children are at risk of acute illness, exposed to nephrotoxic medications, and susceptible to rare but severe infections and immunologic insults that may contribute to AKI and chronic kidney disease (CKD). In some, CKD can progress to kidney failure with replacement therapy (KFRT). CKD and KFRT are associated with increased morbidity and mortality in this patient population. Therefore, it is critical to monitor for and recognize the risk factors for kidney injury in this population and mitigate these risks. In this paper, the authors provide an overview of kidney disease pertaining to heart and liver transplantation in children with guidance on monitoring, diagnosis, prevention, and management.

Efficacy and safety of maralixibat treatment in patients with Alagille syndrome and cholestatic pruritus (ICONIC): a randomised phase 2 study

BACKGROUND

Alagille syndrome is a rare genetic disease that often presents with severe cholestasis and pruritus. There are no approved drugs for management. Maralixibat, an apical, sodium-dependent, bile acid transport inhibitor, prevents enterohepatic bile acid recirculation. We evaluated the safety and efficacy of maralixibat for children with cholestasis in Alagille syndrome.

METHODS

ICONIC was a placebo-controlled, randomised withdrawal period (RWD), phase 2b study with open-label extension in children (aged 1-18 years) with Alagille syndrome (NCT02160782). Eligible participants had more than three times the normal serum bile acid (sBA) levels and intractable pruritus. After 18 weeks of maralixibat 380 μg/kg once per day, participants were randomly assigned (1:1) to continue maralixibat or receive placebo for 4 weeks. Subsequently, all participants received open-label maralixibat until week 48. During the long-term extension (204 weeks reported), doses were increased up to 380 μg/kg twice per day. The primary endpoint was the mean sBA change during the RWD in participants with at least 50% sBA reduction by week 18. Cholestastic pruritus was assessed using observer-rated, patient-rated, and clinician-rated 0-4 scales. The safety population was defined as all participants who had received at least one dose of maralixibat. This trial was registered with ClinicalTrials.gov, NCT02160782, and is closed to recruitment.

FINDINGS

Between Oct 28, 2014, and Aug 14, 2015, 31 participants (mean age 5·4 years [SD 4·25]) were enrolled and 28 analysed at week 48. Of the 29 participants who entered the randomised drug withdrawal period, ten (34%) were female and 19 (66%) were male. In the RWD, participants switched to placebo had significant increases in sBA (94 μmol/L, 95% CI 23 to 164) and pruritus (1·7 points, 95% CI 1·2 to 2·2), whereas participants who continued maralixibat maintained treatment effect. This study met the primary endpoint (least square mean difference -117 μmol/L, 95% CI -232 to -2). From baseline to week 48, sBA (-96 μmol/L, -162 to -31) and pruritus (-1·6 pts, -2·1 to -1·1) improved. In participants who continued to week 204 (n=15) all improvements were maintained. Maralixibat was generally safe and well tolerated throughout. The most frequent adverse events were gastrointestinal related. Most adverse events were self-limiting in nature and mild-to-moderate in severity.

INTERPRETATION

In children with Alagille syndrome, maralixibat is, to our knowledge, the first agent to show durable and clinically meaningful improvements in cholestasis. Maralixibat might represent a new treatment paradigm for chronic cholestasis in Alagille syndrome.

FUNDING

Mirum Pharmaceuticals.

Ocular manifestations of liver disease in children: Clinical aspects and implications

Liver and eyes are interlinked to each other in various medical conditions. There are certain ocular findings which directly indicate specific liver disorders. Thus, it becomes critical to identify disorders of liver and eyes early in the course of illness, so that prompt management may be initiated before the commencement of complications. It is highly advantageous in metabolic liver disorders as it offers prognostic value and spares the patient of unnecessary invasive and detailed work up. However, due to its silent and heterogeneous presentation, it is often unrecognized and ignored. Eye abnormalities could be due to, either direct toxic effects of abnormal metabolites, excess of normal metabolites, or by deficient energy metabolism. A number of inherited liver conditions have associated ocular lesions such as Kayser-Fleischer rings in Wilson's disease, posterior embryotoxon or optic drusen in Alagille's syndrome, and cherry-red spot in Niemann-Pick's type A. A thorough eye examination is important in distinguishing between several different forms of familial intrahepatic cholestasis which are associated with anomalies of the heart, bones, or kidneys. Early diagnosis is important, as in most cases, dietary restriction and early therapy prevents the onset of disability. The aim of this review is to sensitize and make pediatricians, hepatologists and ophthalmologists aware of specific ocular findings, suggestive of certain hepatobiliary disorders, thus helping in early referral. The pediatric and adult literature was thoroughly reviewed to organize the present review.

Risk Factors Affecting Outcomes in Pediatric Liver Transplantation: A Real-World Single-Center Experience

Background

Despite liver transplantation (LT) being the standard treatment for pediatric end-stage liver disease, complications often persist and can adversely affect the post-transplant outcomes. This study aimed to identify the risk factors affecting the outcomes in pediatric LT patients.

Material/Methods

Data from pediatric patients who underwent primary LT from March 1988 to December 2018 were retrospectively analyzed. Chronic liver disease was defined as an explanted liver showing fibrosis regardless of grade, cirrhosis, or any other underlying disease that may cause progressive liver injury leading to fibrosis or cirrhosis.

Results

A total of 255 pediatric patients underwent LT during the study period. Their 1-, 5-, and 10-year overall survival rates were 90.5%, 88.4%, and 87.8%, respectively. According to multivariate analysis, while liver disease without underlying chronic liver disease (P=0.024) and a pediatric end-stage liver disease (PELD) score ≥30 (P=0.036) were the only factors associated with worse survival, body weight <6 kg (P=0.050), whole-liver DDLT compared to LDLT (P=0.001), fulminant liver failure (P=0.008), and postoperative hepatic artery complications (P<0.001) were associated with worse graft survival. Liver disease without underlying chronic liver disease was the only factor independently associated with hepatic artery complications (P=0.003).

Conclusions

Greater caution is recommended in pediatric patients with liver disease unaccompanied by underlying chronic liver disease, high PELD score, or low body weight to improve survival after LT. Hepatic artery complication was the only surgical complication affecting the graft survival outcome, especially in patients having liver disease without underlying chronic liver disease.

Combined Liver Kidney Transplant in Adult Patient With Alagille Syndrome and Pulmonary Hypertension

In this article, we describe a case of a 33-year-old female with Alagille syndrome complicated by bilateral branch pulmonary artery stenosis resulting in moderate pulmonary hypertension, end-stage liver disease complicated by portal hypertension, and chronic renal disease who presented for combined liver-kidney transplant. Alagille syndrome is an autosomal dominant disease affecting the liver, heart, and kidneys. Multidisciplinary preoperative evaluation was performed with a team consisting of a congenital heart disease cardiologist, a cardiac anesthesiologist, a nephrologist, and a transplant surgeon. We describe Alagille syndrome and our intraoperative management. To our knowledge, this is the first description of a combined liver-kidney transplant in an adult patient with Alagille syndrome.

Pediatric biliary disorders: Multimodality imaging evaluation with clinicopathologic correlation

The spectrum of pathologies affecting the biliary tree in the pediatric population varies depending on the age of presentation. While in utero insults can result in an array of anatomic variants and congenital anomalies in newborns, diverse acquired biliary pathologies are observed in older children. These acquired pathologies display different presentations and consequences than adults. Multimodality imaging assessment of the pediatric biliary system is requisite to establishing an appropriate management plan. Awareness of the imaging features of the various biliary pathologies and conveying clinically actionable information is essential to facilitate appropriate patient management. In this paper, we will illustrate the anatomy and embryology of the pediatric biliary system. Then, we will provide an overview of the imaging modalities used to assess the biliary system. Finally, we will review the unique features of the pediatric biliary pathologies, complemented by histopathologic correlation and discussions of clinical management.

Intracranial Hypertension and Papilledema in a Large Cohort of Pediatric Patients With Alagille Syndrome

AIMS AND BACKGROUND

Ophthalmic abnormalities are amongst the 5 major criteria required for a diagnosis of Alagille syndrome (ALGS), of which embryotoxon, pseudopapilledema, and hypopigmented retinopathy are the most common. Papilledema with or without intracranial hypertension (ICHT) is rarely described. We report 9 pediatric cases of ALGS with bilateral papilledema, 5 of which were diagnosed with ICHT.

METHODS

The ophthalmic data from 85 patients with clinically and/or genetically (n = 37) proven ALGS were reviewed. The study inclusion criteria were a positive diagnosis of ALGS and availability of ophthalmic follow-up data. Ophthalmic data from 40 patients after liver transplantation (LT) for other indications were also analyzed.

RESULTS

Nine (13.0%) of the 69 patients meeting the inclusion criteria had papilledema. The neurological and neuroimaging results in all 9 patients were normal. These 9 patients were categorized into 4 groups: a nontransplant group (n = 1), a group with pretransplant papilledema persistent after LT (n = 2), a group with papilledema occurring after LT with spontaneous resolution (n = 1), and a group with papilledema and signs of ICHT after LT (n = 5). The patients with ICHT were treated with steroids alone (n = 1) or with acetazolamide (n = 4). A ventriculoperitoneal shunt was placed in 2 of the 5 cases because of progressive visual loss. Pseudopapilledema was present in 10 additional patients (14.5%, 10/69). One (2.5%) of the 40 patients without ALGS developed papilledema after LT.

CONCLUSIONS

True ICHT may be underdiagnosed in patients with ALGS. Our findings underscore the need for close ophthalmic follow-up before and after LT in these patients.

Paediatric cholestatic liver disorders for the adult gastroenterologist: a practical guide

With improvements in the outcomes for cholestatic liver diseases that present in childhood, increasing numbers of patients will require ongoing care as adults. The recent advances in management options coupled with the fact that each adult physician will have a limited number of patients with these conditions means there is a need for those in adult services to develop expertise in these conditions that were historically the domain of paediatrics. This review provides an overview of the most common paediatric cholestatic liver diseases and outlines the clinical manifestations and potential complications, and identifies key management issues unique to each condition for effective ongoing care of these patients.

Potential of ileal bile acid transporter inhibition as a therapeutic target in Alagille syndrome and progressive familial intrahepatic cholestasis

Alagille syndrome (ALGS) and progressive familial intrahepatic cholestasis (PFIC) are rare, inherited cholestatic liver disorders that manifest in infants and children and are associated with impaired bile flow (ie cholestasis), pruritus and potentially fatal liver disease. There are no effective or approved pharmacologic treatments for these diseases (standard medical treatments are supportive only), and new, noninvasive options would be valuable. Typically, bile acids undergo biliary secretion and intestinal reabsorption (ie enterohepatic circulation). However, in these diseases, disrupted secretion of bile acids leads to their accumulation in the liver, which is thought to underlie pruritus and liver-damaging inflammation. One approach to reducing pathologic bile acid accumulation in the body is surgical biliary diversion, which interrupts the enterohepatic circulation (eg by diverting bile acids to an external stoma). These procedures can normalize serum bile acids, reduce pruritus and liver injury and improve quality of life. A novel, nonsurgical approach to interrupting the enterohepatic circulation is inhibition of the ileal bile acid transporter (IBAT), a key molecule in the enterohepatic circulation that reabsorbs bile acids from the intestine. IBAT inhibition has been shown to reduce serum bile acids and pruritus in trials of paediatric cholestatic liver diseases. This review explores the rationale of inhibition of the IBAT as a therapeutic target, describes IBAT inhibitors in development and summarizes the current data on interrupting the enterohepatic circulation as treatment for cholestatic liver diseases including ALGS and PFIC.

Living donor liver transplantation in Alagille syndrome-Single center experience from south Asia

To analyze the clinical characteristics and the outcomes of living donor liver transplantation in children with Alagille syndrome (AGS). Clinical data of children with AGS who underwent liver transplantation between July 2009 and May 2019 in our unit were retrospectively analyzed. Primary end-points were patient and graft survival. Ten children with AGS underwent living donor liver transplantation at a median age of 28 months (range, 12-84 months). Jaundice was the most common initial symptom and was noted after a median duration of 20 days after birth (range, 7-60 days). Two patients had undergone Kasai porto-enterostomy for misdiagnosis of biliary atresia. The most common indication for transplantation was severe pruritus with poor quality of life. Explant livers in three children showed cirrhosis with early well-differentiated hepatocellular carcinoma. We have 100% patient and graft survival at a mean follow-up of 32 months (range 3-72 months). The median z-score for weight and height at liver transplantation was -2.66 (range: -6.44 to -0.9) and -3.6 (range: -7.96 to -0.93) while at follow-up was -1.7 (range: -3.4 to -0.35) and -2.1 (range: -3.9 to -1.4), respectively. The estimated glomerular filtration rate was normal pretransplant and follow-up. This is the first series of LDLT for Alagille syndrome in the Indian sub-continent. We report excellent post-transplant outcomes in contrast to outcomes reported from Western literature.

Neonatal cholestasis: recent insights

Background

Neonatal physiological jaundice is a common benign condition that rarely extends behind the second week of life; however, it may interfere with the diagnosis of a pathological condition termed neonatal cholestasis (NC). The latter is a critical, uncommon problem characterized by conjugated hyperbilirubinaemia. This review aims to highlight the differences between physiological and pathological jaundice, identify different causes of NC, and provide a recent approach to diagnosis and management of this serious condition.

Main text

NC affects 1/2500 live births, resulting in life-threatening complications due to associated hepatobiliary or metabolic abnormalities. NC is rarely benign and indicates the presence of severe underlying disease. If jaundice extends more than 14 days in full-term infants or 21 days in preterm infants, the serum bilirubin level fractionated into conjugated (direct) and unconjugated (indirect) bilirubin should be measured. A stepwise diagnostic approach starts with obtaining a complete history, and a physical examination which are valuable for the rapid diagnosis of the underlying disease. The most frequently diagnosed causes of NC are biliary atresia (BA) and idiopathic neonatal hepatitis (INH). The early diagnosis of NC ensures more accurate management and better prognosis. Despite the unavailability of any specific treatments for some causes of NC, the patient can benefit from nutritional management and early medical intervention. Future research should attempt to shed light on methods of screening for NC, especially for causes that can be effectively treated either through proper nutritional support, appropriate chemotherapeutic management, or timely surgical intervention.

Conclusion

Further attention should be paid for diagnosis and treatment of NC as it may be misdiagnosed as physiological jaundice; this may delay the proper management of the underlying diseases and aggravates its complications.

The Roles of Notch Signaling in Liver Development and Disease

The Notch signaling pathway plays major roles in organ development across animal species. In the mammalian liver, Notch has been found critical in development, regeneration and disease. In this review, we highlight the major advances in our understanding of the role of Notch activity in proper liver development and function. Specifically, we discuss the latest discoveries on how Notch, in conjunction with other signaling pathways, aids in proper liver development, regeneration and repair. In addition, we review the latest in the role of Notch signaling in the pathogenesis of liver fibrosis and chronic liver disease. Finally, recent evidence has shed light on the emerging connection between Notch signaling and glucose and lipid metabolism. We hope that highlighting the major advances in the roles of Notch signaling in the liver will stimulate further research in this exciting field and generate additional ideas for therapeutic manipulation of the Notch pathway in liver diseases.

Not only Alagille syndrome. Syndromic paucity of interlobular bile ducts secondary to HNF1β deficiency: a case report and literature review

BACKGROUND

paucity of interlobular bile ducts is an important observation at liver biopsy in the diagnostic work-up of neonatal cholestasis. To date, other than in the Alagille syndrome, syndromic paucity of interlobular bile ducts has been documented in four cholestatic neonates with HFN1β mutations. A syndromic phenotype, known as renal cysts and diabetes syndrome (RCAD), has been identified. This is usually characterized by a wide clinical spectrum, including renal cysts, maturity-onset diabetes of the young, exocrine pancreatic insufficiency, urogenital abnormalities and a not well established liver involvement. Herein we report a novel case of paucity of interlobular bile ducts due to an HFN1β defect.

CASE PRESENTATION

A 5-week-old boy was admitted to our department for cholestatic jaundice with increased gamma-glutamyl transpeptidase and an unremarkable clinical examination. He had been delivered by Caesarian section at 38 weeks' gestation from unrelated parents, with a birth weight of 2600 g (3rd percentile). Screening for cholestatic diseases, including Alagille syndrome, was negative except for a minor pulmonary artery stenosis at echocardiography and a doubt of a thoracic butterfly hemivertebra. The finding of hyperechogenic kidneys with multiple bilateral cortical cysts at ultrasound examination, associated with moderately impaired renal function with proteinuria, polyuria and metabolic acidosis, was suggestive of ciliopathy. A liver biopsy was performed revealing paucity of interlobular bile ducts, thus the diagnosis of Alagille syndrome was reconsidered. Although genetic tests for liver cholestatic diseases were performed with negative results for Alagille syndrome (JAG1 and NOTCH2), a de-novo missense mutation of HNF1β gene was detected. At 18 months of age our patient has persistent cholestasis and his itching is not under satisfactory control.

CONCLUSIONS

Alagille syndrome may not be the only syndrome determining paucity of interlobular bile ducts in neonates presenting with cholestasis and renal impairment, especially in small for gestational age newborns. We suggest that HNF1β deficiency should also be ruled out, taking into consideration HNF1β mutations, together with Alagille syndrome, in next generation sequencing strategies in neonates with cholestasis, renal impairment and/or paucity of interlobular bile ducts at liver biopsy.

Alagille Syndrome and the Liver: Current Insights

Alagille syndrome (ALGS) is an autosomal dominant disorder, with multisystem involvement, which usually occurs due to Notch signaling pathway defects, mostly due to JAG1 mutation (ALGS type 1), but rarely due to neurogenic locus notch homolog protein (NOTCH2) mutation (ALGS type 2). It was suspected in cases having at least three out of five major clinical criteria: cholestasis with a paucity of the bile duct, congenital cardiac defects, ocular posterior embryotoxon, typical facial features, and skeletal malformation. Till date, no early predictive marker for hepatic outcome in ALGS has found. No genotypic or, phenotype features or correlation could predict the development of endstage liver disease, which poses a unique management challenge. Cases with progressive liver damage, unremitting cholestasis and intractable pruritus often depend on liver transplantation as last resort. The cardiac, and renal status should be well accessed before liver transplant for the better post-transplantation outcome. Most of the clinical manifestations usually improve the following transplant, except any change in stature. The post liver transplantation outcome was usually comparable with other conditions which require liver transplantation as a last resort, but in this disease the effect of long term immunosuppression on other affected systems not evaluated well till date. Therefore long term post transplant prospective study is required to address these issues.

How to cite this article: Singh SP, Pati GK. Alagille Syndrome and the Liver: Current Insights. Euroasian J Hepatogastroenterol, 2018;8(2):140-147

Alagille Syndrome

Alagille syndrome is a complex multisystem autosomal dominant disorder with a wide variability in penetrance of clinical features. A majority of patients have pathogenic mutations in either the JAG1 gene, encoding a Notch pathway ligand, or the receptor NOTCH2. No genotype-phenotype correlations have been found in any organ system. Liver disease is a major cause of morbidity in this population, whereas cardiac and vascular involvement accounts for most of the mortality. Current therapies are supportive, but the future is promising for the development of targeted interventions to augment Notch pathway signaling in involved tissues.

Alagille Syndrome: An Overview

Alagille syndrome (AGS) is a highly complex, multisystem, autosomal dominant disorder that is caused by a defect in the Notch signaling pathway. This syndrome mainly affects the liver, causing significant cholestasis, which is caused by a paucity of intrahepatic bile ducts. There can be cardiac involvement, including, but not limited to, pulmonary stenosis and tetralogy of Fallot. Patients can also present with butterfly vertebra, ocular issues, and vascular events. Because this syndrome follows an autosomal dominant inheritance, it can have variable expression even in the same family line. For infants in the NICU who have a cardiac defect and persistent hyperbilirubinemia after two weeks of age, genetic testing for AGS should be considered. Early detection and diagnosis can lead to improved outcomes. In this discussion of AGS, the clinical features as well as management are discussed.

Imaging findings of Alagille syndrome in young infants: differentiation from biliary atresia

OBJECTIVE

To compare the imaging findings using ultrasonography, MR cholangiopancreatography (MRCP), and intraoperative cholangiography (IOC) between Alagille syndrome (AGS) and biliary atresia (BA) in young infants with cholestatic jaundice.

METHODS

The institutional review board approved this retrospective study. Ultrasonography (n = 55), MRCP (n = 33), and IOC (n = 22) studies were performed in 55 infants (all younger than 3 months) with AGS (n = 7) and BA (n = 48). The ultrasound images were reviewed focusing on gallbladder (GB) abnormalities, triangular cord sign, hepatic artery enlargement and signs of portal hypertension. Visualization of the extrahepatic biliary tree was assessed by MRCP and IOC.

RESULTS

Six (86%) AGS patients showed a small GB on ultrasound; this was comparable to that in BA patients (81%, 35/43). The images were negative for triangular cord sign and hepatic artery enlargement in all AGS patients, whereas they were positive in 48% (23/48) (p = 0.034) and 77% (33/43) (p < 0.001) of the BA patients, respectively. Signs of portal hypertension were less common in AGS patients than in BA patients (p = 0.010). Although non-visualization of the extrahepatic biliary tree by MRCP did not differ significantly between patients with AGS and BA, AGS patients showed a higher proportion of visible common bile ducts with IOC, compared to BA patients. The diagnosis of AGS was made in four infants (57%) before ultrasonography, based on extrahepatic manifestations.

CONCLUSION

The small GB visualized on ultrasonography and non-visualization of extrahepatic biliary tree by MRCP commonly occurred in patients with either AGS or BA. However, triangular cord sign, hepatic artery enlargement and signs of portal hypertension onultrasonography and non-visualized common bile duct with IOC were less frequent in AGS patients than in BA patients. Advances in knowledge: Atypical imaging findings for BA should prompt a meticulous evaluation for the extrahepatic manifestations of AGS to avoid possibly harmful surgery.

The management of childhood liver diseases in adulthood

An increasing number of patients with childhood liver disease survive into adulthood. These young adults are now entering adult services and require ongoing management. Aetiologies can be divided into liver diseases that develop in young adults which present to adult hepatologists i.e., biliary atresia and Alagille syndrome or liver diseases that occur in children/adolescents and adults i.e., autoimmune hepatitis or Wilson's disease. To successfully manage these young adults, a dynamic and responsive transition service is essential. In this review, we aim to describe the successful components of a transition service highlighting the importance of self-management support and a multi-disciplinary approach. We will also review some of the liver specific aetiologies which are unique to young adults, offering an update on pathogenesis, management and outcomes.

Atypical causes of cholestasis

Cholestatic liver disease consists of a variety of disorders. Primary sclerosing cholangitis and primary biliary cirrhosis are the most commonly recognized cholestatic liver disease in the adult population, while biliary atresia and Alagille syndrome are commonly recognized in the pediatric population. In infants, the causes are usually congenital or inherited. Even though jaundice is a hallmark of cholestasis, it is not always seen in adult patients with chronic liver disease. Patients can have “silent” progressive cholestatic liver disease for years prior to development of symptoms such as jaundice and pruritus. In this review, we will discuss some of the atypical causes of cholestatic liver disease such as benign recurrent intrahepatic cholestasis, progressive familial intrahepatic cholestasis, Alagille Syndrome, biliary atresia, total parenteral nutrition induced cholestasis and cholestasis secondary to drug induced liver injury.

Medical and dental management of Alagille syndrome: a review

Alagille syndrome is a rare, autosomal, complex, dominant disorder associated with dysfunction of the liver, heart, skeleton, and eyes, as well as characteristic facial appearance. It is associated with the defect in component of the Notch signalling pathway. Here, we review the main features of Alagille syndrome with special focus on oro-facial manifestations like prominent forehead, moderate hypertelorism with deep-set eyes, a saddle or straight nose with a flattened, bulbous tip, and large ears. The article is based on the most recent and significant literature available from the Medline database.

Contrary to healthy children, patients with Alagille syndrome have many problems, depending on several factors like the severity of cholestasis and scarring in the liver, heart or lung problems, presence of infections, or other problems related to poor nutrition that can manifest in their oral cavity in the dental and periodontal tissues, as well as oral mucosa. From the dentist’s view, the most important elements are careful observation, accurate diagnosis, and planned management of such patients, especially during the patient’s formative years, to prevent complications. Aggressive preventive oral care and consultations with medical specialists before any invasive procedure are obligatory. All this can improve quality of life in patients with Alagille syndrome.

Alagille syndrome: experience of a tertiary care center in North India

Alagille syndrome (AGS) is an autosomal dominant disorder of chronic cholestasis characterized by paucity of interlobular bile ducts. The condition has been described only as isolated case reports in India. We describe clinical profile and outcome of nine subjects (six infants and three older children) with AGS. Cholestasis and characteristic facies were present in all, followed by congenital heart disease, vertebral anomalies, and posterior embryotoxon in seven, five, and four cases, respectively. Pruritus was the commonest symptom which was refractory to medical treatment in one third of cases. Two cases developed decompensated liver disease on follow up. High index of suspicion for this multisystemic condition is essential for correct diagnosis and management.

Management of cholestatic pruritus in paediatric patients with alagille syndrome: the King's College Hospital experience

OBJECTIVES

The aims of the study were to perform a retrospective observational review of the present management and outcome of cholestatic pruritus in children with Alagille syndrome (AGS) at King's College Hospital and to use results to inform appropriate guidelines.

METHODS

A retrospective review of 62 patients diagnosed as having AGS from January 1995 to November 2010 treated at King's College Hospital was performed. The departmental database of the Paediatric Liver Centre was searched to identify all patients and the clinical records were then analysed.

RESULTS

Fifty-one (82.3%) patients experienced pruritus and 50 (80.6%) received antipruritic medication. Ursodeoxycholic acid was the most prescribed drug (n = 40). Other drugs prescribed were rifampicin (n = 39), cholestyramine (n = 18), naltrexone (n = 14), alimemazine (n = 13), nonsedating antihistamine agents (n = 7), ondansetron (n = 5), and phenobarbitone (n = 1). Albumin dialysis using the molecular adsorbent recirculation system was used in 1 patient. Sixteen patients (25.8%) were listed for liver transplantation, and 11 had undergone transplantation by November 2010. Patient survival was high at 95.2%. Pruritus resolved permanently in 39.2% (n = 20) of patients. Fifty-five percent (n = 11) of such patients had undergone liver transplantation. Pruritus was controlled by medication in 41.2% (n = 21). Itching remained a significant problem, affecting quality of life in 19.6% of patients (n = 10).

CONCLUSIONS

The management of cholestatic pruritus in AGS is difficult and often suboptimal. Pruritus may remain intractable even with combination medical treatment, and at this stage, surgery or liver transplantation is indicated. At our centre, pruritus was successfully treated in 80.4% of patients with medical and surgical management.

Renal involvement and the role of Notch signalling in Alagille syndrome

Alagille syndrome is an autosomal dominant disorder with variable multisystem organ involvement that is caused by mutations in one of two genes in the Notch signalling pathway, JAG1 or NOTCH2. Alagille syndrome is characterized by bile duct paucity, along with at least three of the following features: cholestasis, cardiac defects, skeletal abnormalities, ocular abnormalities and characteristic facies. However, the clinical features of Alagille syndrome are highly variable, and children or adults may also present with predominantly renal findings and little or no hepatic involvement. Renal involvement occurs in 40% of JAG1-mutation-positive individuals. Renal insufficiency is common and has been specifically reported in children with Alagille syndrome who have end-stage liver disease. The role of NOTCH2 and JAG1 in formation of proximal nephron structures and podocytes might explain the observed phenotypes of renal dysplasia and proteinuria in patients with Alagille syndrome, and renal tubular acidosis may be the result of JAG1 expression in the collecting ducts. Renal vascular hypertension in patients with Alagille syndrome is explained by the widespread vasculopathy and the role of Notch signalling in vascular development. Increased awareness of Alagille syndrome amongst nephrologists may lead to more diagnoses of Alagille syndrome in patients with apparently isolated renal disease.

Liver transplant for cholestatic liver diseases

Cholestatic liver diseases include a group of diverse disorders with different epidemiology, pathophysiology, clinical course, and prognosis. Despite significant advances in the clinical care of patients with cholestatic liver diseases, liver transplant (LT) remains the only definitive therapy for end-stage liver disease, regardless of the underlying cause. As per the United Network for Organ Sharing database, the rate of cadaveric LT for cholestatic liver disease was 18% in 1991, 10% in 2000, and 7.8% in 2008. This review summarizes the available evidence on various common and rare cholestatic liver diseases, disease-specific issues, and pertinent aspects of LT.

Alagille syndrome: an overview

Alagille syndrome is an embryofoetopathy, due to mutations in the gene JAG1. It is autosomic dominant with variable expressivity, or sporadic. Neonatal cholestasis is a main feature, due to the paucity of intrahepatic bile ducts. It can rarely develop into cirrhosis, but be responsible for a disabling pruritus and xanthomas. The other features are a peculiar facies, cardiac abnormalities, butterfly vertebrae, and ocular embryotoxon. The prognosis depends on the severity of the liver and heart diseases. Hepatocarcinoma has been reported.

Cutaneous manifestations of common liver diseases

Skin functions as a window to our overall health and a number of systemic diseases result in various cutaneous changes. Knowledge of these manifestations helps in suspecting an underlying systemic illness. Cutaneous abnormalities are quite common in patients with liver diseases and this article aims to focus on these dermatoses. Cutaneous manifestations seen in patients with liver disease though common are nonspecific. They can also be seen in patients without liver diseases and generally do not indicate about a specific underlying hepatic disorder. The presence of a constellation of signs and symptoms is more useful in pointing toward an underlying hepatobiliary condition. The commonest symptom in patients with liver disease is pruritus which is often protracted and disabling. Other common features include spider angiomas, palmar erythema, paper money skin, xanthelasmas, pigmentary changes, and nutritional deficiencies. In this article, first the common cutaneous manifestations that may be associated with liver disorders are discussed and then common liver diseases with their specific cutaneous findings are discussed. Cutaneous abnormalities may be the first clue to the underlying liver disease. Identifying them is crucial for early diagnosis and better management.

Renal anomalies in Alagille syndrome: a disease-defining feature

Alagille syndrome (ALGS) is an autosomal dominant condition, primarily caused by mutations in JAGGED1. ALGS is defined by cholestatic liver disease, cardiac disease and involvement of the face, skeleton, and eyes with variable expression of these features. Renal involvement has been reported though not formally described. The objective of this study was to systematically characterize the renal involvement in ALGS. We performed a retrospective review of 466 JAGGED1 mutation-positive ALGS patients. Charts were reviewed for serum biochemistries, renal ultrasounds or other imaging, urinalysis, and clinical reports from pediatric nephrologists. The clinical data were reviewed by two pediatric hepatologists and a pediatric nephrologist. Of 466 charts reviewed we found 187 yielded evaluable renal information. Of these, 73/187 were shown to have renal involvement, representing 39% of the study cohort. Renal dysplasia was the most common anomaly seen. Genotype analysis of the JAGGED1 mutations in the patients with and without renal involvement did not reveal an association with mutation type. From the study we concluded that renal involvement has a prevalence of 39% in ALGS in our evaluable patients. Renal dysplasia is the most common renal anomaly. This finding correlates with the known role of the Notch pathway in glomerular development. Since renal disease of the type seen in ALGS can impair growth and impact liver transplantation, there is a clear need for a prospective study of renal involvement in ALGS and the development of guidelines for evaluation and management. These data also suggest that renal involvement be considered the sixth defining criterion for ALGS.

Alagille syndrome: pathogenesis, diagnosis and management

Alagille syndrome (ALGS), also known as arteriohepatic dysplasia, is a multisystem disorder due to defects in components of the Notch signalling pathway, most commonly due to mutation in JAG1 (ALGS type 1), but in a small proportion of cases mutation in NOTCH2 (ALGS type 2). The main clinical and pathological features are chronic cholestasis due to paucity of intrahepatic bile ducts, peripheral pulmonary artery stenosis, minor vertebral segmentation anomalies, characteristic facies, posterior embryotoxon/anterior segment abnormalities, pigmentary retinopathy, and dysplastic kidneys. It follows autosomal dominant inheritance, but reduced penetrance and variable expression are common in this disorder, and somatic/germline mosaicism may also be relatively frequent. This review discusses the clinical features of ALGS, including long-term complications, the clinical and molecular diagnosis, and management.

Biliary disease in children

Biliary diseases in children are infrequent; however, they can be associated with high morbidity and mortality if an accurate diagnosis is not made and adequate treatment provided in a timely fashion. Biliary atresia, choledochal cysts, gallbladder disease, and Alagille syndrome can be associated with similar clinical symptoms, laboratory findings, and radiographic findings, which makes accurate diagnosis difficult. The correct treatment for each of these clinical entities is different and can significantly reduce morbidity and mortality from these diseases. In this article, we discuss the epidemiology, approach to diagnosis, prognosis, and treatment modalities for these four disease processes.

Dermatologic disorders and the liver

Chronic liver disease is associated with several cutaneous manifestations. Although many of these changes are nonspecific, some are associated with distinct liver diseases and correlate with the severity of hepatic pathology. Often the first clue to a liver disease is manifested through skin. Although cirrhosis is associated with spider nevi and palmar erythema, disorders can result in noncirrhotic cutaneous manifestations. It is important for physicians to be familiar with the spectrum of these manifestations, to recognize, help detect, and treat the underlying hepatic disease. This article reviews the medical literature and discusses the spectrum of dermatologic manifestations of liver disorders and their pathogenesis, significance, and treatment.

Defects in hepatic Notch signaling result in disruption of the communicating intrahepatic bile duct network in mice

Abnormal Notch signaling in humans results in Alagille syndrome, a pleiotropic disease characterized by a paucity of intrahepatic bile ducts (IHBDs). It is not clear how IHBD paucity develops as a consequence of atypical Notch signaling, whether by a developmental lack of bile duct formation, a post-natal lack of branching and elongation or an inability to maintain formed ducts. Previous studies have focused on the role of Notch in IHBD development, and demonstrated a dosage requirement of Notch signaling for proper IHBD formation. In this study, we use resin casting and X-ray microtomography (microCT) analysis to address the role of Notch signaling in the maintenance of formed IHBDs upon chronic loss or gain of Notch function. Our data show that constitutive expression of the Notch1 intracellular domain in bi-potential hepatoblast progenitor cells (BHPCs) results in increased IHBD branches at post-natal day 60 (P60), which are maintained at P90 and P120. By contrast, loss of Notch signaling via BHPC-specific deletion of RBP-J (RBP KO), the DNA-binding partner for all Notch receptors, results in progressive loss of intact IHBD branches with age. Interestingly, in RBP KO mice, we observed a reduction in bile ducts per portal vein at P60; no further reduction had occurred at P120. Thus, bile duct structures are not lost with age; instead, we propose a model in which BHPC-specific loss of Notch signaling results in an initial developmental defect resulting in fewer bile ducts being formed, and in an acquired post-natal defect in the maintenance of intact IHBD architecture as a result of irresolvable cholestasis. Our studies reveal a previously unappreciated role for Notch signaling in the post-natal maintenance of an intact communicating IHBD structure, and suggest that liver defects observed in Alagille syndrome patients might be more complex than bile duct paucity.

Medical management of Alagille syndrome

Alagille syndrome is a highly variable, autosomal dominant disorder that affects the liver, heart, eyes, face, skeleton, kidneys, and vascular system. Much has been learned about the genetics of this disorder, which is caused primarily by mutations in the Notch signaling pathway ligand JAGGED1; however, the medical management of this condition is complex and continues to generate controversy. The significant variability of organ involvement requires the managing physician to have an understanding of the breadth and interplay of the variable manifestations. Furthermore, the liver disease in particular requires an appreciation of the natural history and evolution of the profound cholestasis.