Alagille's syndrome associated with cystic renal disease

Congenital hepatic fibrosis and its mimics: a clinicopathologic study of 19 cases at a single institution

Background

Congenital hepatic fibrosis (CHF) is a rare inherited form of ductal plate malformation associated with polycystic kidney disease. The diagnosis requires histopathologic confirmation, but can be challenging to distinguish from other undefined fibrocystic liver diseases. We aimed to describe the clinicopathologic features of congenital hepatic fibrosis (CHF), with comparisons to other entities that may clinically and/or histologically mimic CHF.

Methods

Nineteen cases that carried a clinical and/or histologic impression of CHF were identified at our institution, of which the histology was reassessed and reappraised into two categories: CHF (n=13) and mimics (n=6). The clinicopathologic features between the two groups were analyzed and compared.

Results

The CHF group was further sub-classified into those with clinical suspicion (CHF-c, n=8) and those as incidental histology findings (CHF-i, n=5). Patients of CHF-i were much older than CHF-c or mimics (P<0.05). Male and female were equally affected. Six of 8 CHF-c (66.7%) had concurrent kidney diseases, including 5 polycystic kidney diseases. Five of 6 mimics (83.3%) had various kidney diseases, including nephronophthisis, Alport syndrome, renal agenesis, and nephrolithiasis. None of the CHF-i patients had kidney disease, but 3 were associated with hepatic carcinomas. Histology analysis demonstrated characteristic triads (bile duct abnormalities, portal vein hypoplasia, and fibrosis) in all CHF cases. One mimic had paucity of intrahepatic bile ducts, while the other 5 mimics showed abnormal portal veins and nodular regenerative hyperplasia consistent with hepatoportal sclerosis (HPS).

Conclusions

Our study demonstrates classic histology triad of CHF despite a wide spectrum of clinical presentations. HPS is unexpectedly a clinical mimicker of CHF, which can be distinguished histologically.

Notch signaling regulates Akap12 expression and primary cilia length during renal tubule morphogenesis

Alagille syndrome patients present with loss of function mutations in either JAG1 or NOTCH2. About 40%-50% of patients have kidney abnormalities, and frequently display multicystic, dysplastic kidneys. Additionally, gain-of-function mutations in NOTCH2 are associated with cystic kidneys in Hajdu-Cheney syndrome patients. How perturbations in Notch signaling cause renal tubular cysts remains unclear. Here, we have determined that reduced Notch signaling mediated transcription by ectopic expression of dominant-negative mastermind-like (dnMaml) peptide in the nephrogenic epithelia from after the s-shaped body formation and in the developing collecting ducts results in proximal tubular and collecting duct cysts, respectively. An acute inhibition of Notch signaling for two days during kidney development is sufficient to disrupt tubule formation, and significantly increases Akap12 expression. Ectopic expression of Akap12 in renal epithelia results in abnormally long primary cilia similar to that observed in Notch-signaling-deficient epithelia. Both loss of Notch signaling and elevated Akap12 expression disrupt the ability of renal epithelial cells to form spherical structures with a single lumen when grown embedded in matrix. Interestingly, Akap12 can inhibit Notch signaling mediated transcription, which likely explains how both loss of Notch signaling and ectopic expression of Akap12 result in similar renal epithelial abnormalities. We conclude that Notch signaling regulates Akap12 expression while also ensuring normal primary cilia length and renal epithelial morphogenesis, and suggest that one aspect of diseases associated with defective Notch signaling, such as Alagille syndrome, maybe mechanistically related to ciliopathies.

Molecular genetic characterization of a prenatally detected de novo interstitial deletion of chromosome 20p (20p12-p13) encompassing JAG1 and a literature review of prenatal diagnosis of Alagille syndrome

OBJECTIVE

We present prenatal diagnosis and molecular genetic characterization of a de novo interstitial deletion of chromosome 20p (20p12-p13) and a literature review of prenatal diagnosis of Alagille syndrome (ALGS).

CASE REPORT

A 33-year-old woman underwent amniocentesis at 17 weeks of gestation because of an abnormal result of combined first-trimester screening. Her husband was 35 years old, and there was no family history of congenital malformations. Amniocentesis revealed a karyotype of 46,XY,del(20)(p12p13), and array comparative genomic hybridization analysis on uncultured amniocytes revealed a 3.749-Mb deletion at 20p13-p12.3 and a 1.84-Mb deletion at 20p12.2 encompassing the gene of JAG1. The parental karyotypes were normal. Prenatal ultrasound findings were unremarkable. The fetus postnatally manifested characteristic facial features of ALGS. Postnatal molecular cytogenetic analysis of fetal tissues confirmed the prenatal diagnosis. Polymorphic DNA marker analysis revealed a paternal origin of the deletion.

CONCLUSION

A de novo interstitial 20p deletion can be caused by a paternal effect. Pregnancy with a fetus affected with ALGS may be associated with an abnormal result of combined first-trimester screening and manifest no detectable ultrasound abnormalities.

Immune dysregulation in Alagille syndrome: A new feature of the evolving phenotype

Alagille syndrome (ALGS) is a rare autosomal dominant, multi-system disease caused by mutations in one of two NOTCH signaling pathway genes. Mutations in JAG1 are found in more than 94% of patients, with associated Jagged1 defects. We previously showed that CD46, which is a complement and immune regulator, regulates NOTCH expression during T cell activation after binding to C3b/C4b. We have identified 25% of our ALGS cohort with frequent infections and studied a subgroup of 4 in detail who were not showing current features of infections in order to show if Jagged1 abnormalities could affect immune function. We used cytometric bead arrays and FACS to measure cytokines and cell membrane expression. Resting and activated T cells were studied in both low and high IL-2 concentration to assess the TH1 ability to shift from INFγ to IL-10 production. In vitro initial PBMC cell population and subpopulation assessment were normal but further assessment of the lymphocytes revealed that while NOTCH1 expression and regulation was normal on resting TH1, Jagged1 expression was exaggerated. Resting TH1 cells from some patients exhibited high CD132 levels. Upon activating T cells, TH1 cells managed to produce TNF but failed to produce sufficient IFNγ levels (in two patients TH1 produced no IFNγ). TH2 exhibited exaggerated response with high IL-4 and IL-5 levels. TH1 were unable to down-regulate CD127, resulting in prolonged immune activation, and failed to shift from IFNγ to IL-10 production maintaining high IL-2 levels suggesting an impaired T cell response. Disturbed CD46-Jagged1 interaction may explain recurrent infections among ALGS patients, and could predispose to Th2-driven conditions such as asthma, eczema, food allergies and airway atopy and otitis media. The ALGS description could now be extended to include immune dysregulation.

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.

Alagille syndrome and other hereditary causes of cholestasis

Neonatal conjugated jaundice is a common presentation of hereditary liver diseases, which, although rare, are important to recognize early. Developments in molecular genetic techniques have enabled the identification of causative genes, which has improved diagnostic accuracy for patients and has led to a greater understanding of the molecular pathways involved in liver biology and pathogenesis of liver diseases. This review provides an update of the current understanding of clinical and molecular features of the inherited liver diseases that cause neonatal conjugated jaundice.

Paucity of intrahepatic bile ducts in neonates: the first case series from iran

OBJECTIVE

Paucity of interlobular bile ducts (PIBD), defined as absence or marked decrease in the number of interlobular bile ducts, is one of the causes of neonatal cholestasis. Treatment includes treating the intractable pruritus caused by persistent cholestasis. PIBD can be part of a familial syndrome of cholestasis named Alagille syndrome (AGS). We report clinical status of a case series of Iranian patients with PIBD.

METHODS

In this retrospective study, patients with cholestasis admitted to the pediatric gastroenterology ward in a referral hospital in Shiraz from January 2006 to January 2010 and underwent liver biopsy were evaluated. Clinical and paraclinical status of children with the pathologic diagnosis of PIBD was assessed.

FINDINGS

Disease was presented in all jaundiced patients with aged in average 3 days at presentation. Seven patients had the criteria of AGS. Despite medical treatment, cholestasis was not controlled in 6 (28.6%) patients. Liver transplantation led to the survival of 5 patients while the other patient who did not undergo liver transplantation died at 2 months of age. One patient underwent peritoneal dialysis due to renal insufficiency and died at 9 months of age. After 1-5 years of follow-up, the mortality rate was 9.5%.

CONCLUSION

In patients with intractable cholestasis, only patients that underwent liver transplantation survived. Thus, the most important criterion for liver transplantation in neonatal PIBD is intractable cholestasis. This is the first report that shows AGS can result in neonatal-onset renal insufficiency.

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.

Glomerular basement membrane lipidosis in Alagille syndrome

Alagille syndrome is characterized by a paucity of interlobular bile ducts with chronic cholestasis, cardiac, skeletal, and eye abnormalities and is associated predominantly with JAG1 mutations. Various renal abnormalities have been sporadically described. The classic renal histopathology described in Alagille syndrome is mesangiolipidosis, with lipid deposits predominately confined to the mesangium and minimal deposition within the glomerular basement membrane (GBM). We report a 5-year-old girl with Alagille syndrome who presented with persistent subnephrotic proteinuria and renal tubular acidosis. A renal biopsy showed GBM irregularities (mimicking membranous glomerulonephritis), mesangial sclerosis, and focal segmental glomerulosclerosis (FSGS) on light microscopy. Electron microscopy revealed few lipid inclusions within the mesangium but extensive inclusions along the GBM. These findings are mostly consistent with those reported previously in Alagille syndrome. However, the histologic distribution of lipid vacuoles is seemingly reversed in this patient and is uniquely accompanied by FSGS, emphasizing the spectrum of renal histopathology seen in Alagille syndrome. The proteinuria observed in this patient is likely attributed to significant GBM lipid deposition, which over time may contribute to the development of FSGS.

An unusual cause of hypertension and renal failure: a case series of a family with Alagille syndrome

Alagille Syndrome (OMIM 118450) is a multisystem developmental disorder inherited in an autosomal dominant pattern with variable expression. It commonly manifests in children with early cholestatic jaundice due to paucity of interlobular biliary ducts. Renal involvement is less common but can take various forms including renovascular disease, renal agenesis or hypoplasia, cystic renal disease, mesangiolipidosis, tubulointerstitial nephritis and renal tubular acidosis. We describe a family of Alagille syndrome with JAG 1 mutation running through at least two generations, affecting four members with variable phenotypic expressions and disease severity. Alagille syndrome should be considered in the differential diagnosis of adults with renovascular disease and children with agenesis/dysgenesis of kidney and reflux nephropathy even in the absence of hepatic disease. Renal transplant can be successful in these patients although living related donation may not be appropriate given the high penetrance and variable expression of this condition. This syndrome may cause symptomatic bradyarrhythmias as described in our series.

Intense pruritus and failure to thrive in Alagille syndrome

A 4-year-old girl with failure to thrive and intense pruritus associated with Alagille syndrome is described. The clinical features of this autosomal dominant disorder are reviewed. This case highlights the importance of recognizing the severe pruritus as a manifestation of the disease.

Alagille syndrome: cutaneous manifestations in 38 children

The Alagille syndrome is one of the most common inherited disorders causing chronic liver disease during childhood. During the 1990s, 38 children with Alagille syndrome were evaluated at two pediatric centers in Buenos Aires, Argentina. Characteristic clinical, humoral, and cutaneous features were analyzed. The average age of diagnosis was 29 months old (range of between 2 months and 15 years). Cholestasis was evident in 92% of patients during the neonatal period. Family antecedents related to the syndrome were found in 18.5% of the patients. Peculiar facies developed in 85% of patients. Chronic cholestasis and pruritus were observed in all of the patients and jaundice was evident in 78%. Eighty-four percent of the patients had heart disease (pulmonary stenosis, intraauricular communication, intraventricular communication), 76% of them showed growth retardation, and vertebrae abnormalities were found in 63%. Embryotoxon appeared in 76% of patients, and renal disturbances in 21%. Eleven children (28%) had xanthomas, in the neck, elbows, palms, helixes, inguinal area, gluteus, and knees. The earliest findings appeared in the first months of life, and the latest at 5 years of age. The xanthomas located in the folds had a stony aspect. Cholesterol levels ranging from 220 to 1600 mg percentage (mg%) were demonstrated in all of the children with xanthomas. Liver transplantation was performed in seven of the patients (18.4%). Two of them died after this operation. The disappearance of xanthomas after transplantation was remarkable in all of the patients.

Alagille syndrome

Syndromic paucity of bile ducts or "Alagille syndrome" is characterized by peculiar facies, chronic cholestasis, posterior embryotoxon, butterfly-like vertebral arch defects and peripheral pulmonary artery hypoplasia or stenosis. We present a two-year-old female child with the 'partial' or 'incomplete' Alagille syndrome. The child had three of the five major features of the syndrome. A brief review of literature of the syndrome is presented.

The molecular control of renal branching morphogenesis: current knowledge and emerging insights

Mammalian kidney development requires the formation of a patterned, branched network of collecting ducts, a process termed renal branching morphogenesis. Disruption of renal branching morphogenesis during human kidney development results in renal dysplasia, the major cause of renal failure in young children. Genetic evidence, combined with in vitro data, have implicated transcription factors, secreted growth factors, and cell surface signaling peptides as critical regulators of renal branching morphogenesis. This review discusses the current knowledge regarding the regulation of renal branching morphogenesis in vivo provided by the analysis of genetic mutations in mice and humans which disrupt collecting duct system development. In addition, in vivo and in vitro evidence regarding the functions of several other gene families are considered, rendering new insight into emerging regulatory roles for these molecules in renal branching morphogenesis.

Transforming growth factor-beta induces renal epithelial jagged-1 expression in fibrotic disease

For elucidation of the mechanisms by which growth factors and cytokines affect renal epithelial cells, gene array analysis of renal cells cultured in the presence of transforming growth factor-beta1 (TGF-beta1) was performed. Many genes that were not previously considered to be involved in renal cell biologic processes were affected, one of which was jagged-1. The jagged ligand/notch receptor family controls the formation of boundaries between groups of cells and regulates cell fates. On the basis of the array analysis, jagged-1 expression was further evaluated in cultured cells and in C57BL/6 mice with a model of unilateral ureteral obstruction (UUO). Recombinant human TGF-beta1 increased jagged-1 mRNA levels at concentrations between 10(-11) and 10(-10) M. There was a commensurate increase in jagged-1 protein levels, as assessed by Western blotting. The expression of jagged-1 mRNA and protein was observed to be significantly increased in the kidneys of C57BL/6 mice with obstructed ureters, compared with the contralateral kidneys, at 7 and 14 d of UUO. Immunohistochemical analyses demonstrated jagged-1 expression in distal tubules of kidneys from normal mice or contralateral kidneys from mice with UUO. Jagged-1 protein expression was increased in tubules not yet in apparent atrophy in the kidneys with an obstructed ureter. Jagged-1 expression was significantly increased in the kidneys of normal mice treated with TGF-beta1 and was decreased in the kidneys of mice with UUO treated with a TGF-beta receptor II-Fc chimera. These results suggest that jagged-1 is expressed in normal kidneys and that this expression is upregulated during renal disease, in a TGF-beta-dependent manner.

Pathophysiology of renal disease associated with liver disorders: implications for liver transplantation. Part I

Renal and hepatic function are often intertwined through both the existence of associated primary organ diseases and hemodynamic interrelationships. This connection occasionally results in the chronic failure of both organs, necessitating combined liver-kidney transplantation (LKT). Since 1988, more than 850 patients in the United States have received such transplants, with patient survival somewhat less than that for patients receiving either organ alone. Patients with renal failure caused by acute injury or hepatorenal syndrome have classically not been included as candidates for combined transplantation because of the reversibility of renal dysfunction after liver transplantation. However, the rate and duration of renal failure before liver transplantation is increasing in association with prolonged waiting list times. Thus, the issue of acquired permanent renal damage in the setting of hepatic failure continues to confront the transplant community. The following article and its sequel (Part II, to be published in vol 8, no 3 of this journal) attempt to review the problem of primary and secondary renal disease in patients with end-stage liver disease, elements involved in renal disease progression and recovery, the impact of renal disease on liver transplant outcome, and results of combined LKT; outline the steps in the pretransplantation renal evaluation; and provide the beginnings of an algorithm for making the decision for combined LKT.

Alagille syndrome. The widening spectrum of arteriohepatic dysplasia

Alagille syndrome was described more than 35 years ago as a genetic entity characterized by five major features: chronic cholestasis resulting from paucity of interlobular bile ducts, peripheral pulmonary stenosis, butterflylike vertebral arch defect, posterior embryotoxon, and peculiar facies. Recently, JAGGED1 has been identified as a responsible gene by demonstration of mutations in AGS patients. Studies of the JAGGED1 expression pattern demonstrate that minor features and almost all the elements in the long list of manifestations described in AGS patients are not coincidental. This finding suggests that the definition of AGS may be reconsidered in the light of JAGGED1 mutations.

Variable morbidity in alagille syndrome: a review of 43 cases

BACKGROUND

Alagille syndrome is one of the most common inherited disorders that cause chronic liver disease in children. Early reports suggested a benign course in these patients. Subsequent reports showed significant morbidity and mortality. This study was designed to analyze the long-term clinical course in Alagille syndrome.

METHODS

The records of children with Alagille syndrome seen during a 20-year period were reviewed.

RESULTS

Forty-three patients were identified. Liver disease was diagnosed before 12 months of age in 95%. The frequencies of renal anomalies (50%) and intracranial hemorrhage (12%) were significant. The high incidence of chronic otitis media (35%) has not been reported previously. One patient had a renal transplant. Vascular compromise as a pathologic mechanism for some characteristics of the syndrome is also suggested by the presence of small bowel stenosis and atresia, tracheal and bronchial stenosis, renal artery stenosis, middle aortic syndrome, and avascular necrosis of the humeral and femoral heads. Twenty (47%) patients underwent liver transplantation. Five of six who underwent Kasai procedure required liver transplantation. Twelve died (28%), five after liver transplantation. One patient died of intracranial bleeding. Sixteen (37%) without liver transplantation and 15 (35%) who underwent liver transplantation are alive.

CONCLUSIONS

Some patients with early-onset and more severe liver disease can benefit from liver transplantation. Careful and complete assessment should be made of infants with a cholestatic syndrome, to avoid misdiagnosis and unnecessary Kasai procedures. Our observation of vascular compromise in various organ systems suggests that notch signaling pathway defects affect angiogenesis in Alagille syndrome.

Features of Alagille syndrome in 92 patients: frequency and relation to prognosis

We have studied 92 patients with Alagille syndrome (AGS) to determine the frequency of clinical manifestations and to correlate the clinical findings with outcome. Liver biopsy specimens showed paucity of the interlobular ducts in 85% of patients. Cholestasis was seen in 96%, cardiac murmur in 97%, butterfly vertebrae in 51%, posterior embryotoxon in 78%, and characteristic facies in 96% of patients. Renal disease was present in 40% and intracranial bleeding or stroke occurred in 14% of patients. The presence of intracardiac congenital heart disease was the only clinical feature statistically associated with increased mortality (P <.001). Initial measures of hepatic function in infancy including absence of scintiscan excretion were not predictive of risk for transplantation or increased mortality. The hepatic histology of these AGS patients showed a significant increase in the prevalence of bile duct paucity (P =.002) and fibrosis (P <.001) with increasing age. Liver transplantation for hepatic decompensation was necessary in 21% (19 of 92) of patients with 79% survival 1-year posttransplantation. Current mortality is 17% (16 of 92). The factors that contributed significantly to mortality were complex congenital heart disease (15%), intracranial bleeding (25%), and hepatic disease or hepatic transplantation (25%). The 20-year predicted life expectancy is 75% for all patients, 80% for those not requiring liver transplantation, and 60% for those who required liver transplantation.

Arteriohepatic dysplasia (Alagille syndrome; Watson-Alagille syndrome)

Alagille syndrome (AS) (arteriohepatic dysplasia, Alagille-Watson syndrome) is a multi-system disorder with hepatic, skeletal, eye, cardiac and renal manifestations. It results from mutation of the JAG1 gene, located on chromosome 20, which encodes a ligand for Notch receptor(s). The interactions of Notch receptors and their ligands are crucial in controlling cell fate decisions in a variety of developmental processes. AS varies in its severity, even in the same family, from asymptomatic gene carriers through to lethality due to inoperable cardiac or end-stage liver disease. However, advances in medical and surgical therapy have improved the prognosis at the severe end of the spectrum. It is hoped that the enhanced understanding of the biology of AS resulting from the cloning of the JAG1 gene will enable us to develop additional strategies for more effective treatments.