Renal histopathology in Alagille's syndrome

NOTCH2 mutations in Alagille syndrome

BACKGROUND

Alagille syndrome (ALGS) is a dominant, multisystem disorder caused by mutations in the Jagged1 (JAG1) ligand in 94% of patients, and in the NOTCH2 receptor in <1%. There are only two NOTCH2 families reported to date. This study hypothesised that additional NOTCH2 mutations would be present in patients with clinical features of ALGS without a JAG1 mutation.

METHODS

The study screened a cohort of JAG1-negative individuals with clinical features suggestive or diagnostic of ALGS for NOTCH2 mutations.

RESULTS

Eight individuals with novel NOTCH2 mutations (six missense, one splicing, and one non-sense mutation) were identified. Three of these patients met classic criteria for ALGS and five patients only had a subset of features. The mutations were distributed across the extracellular (N=5) and intracellular domains (N=3) of the protein. Functional analysis of four missense, one nonsense, and one splicing mutation demonstrated decreased Notch signalling of these proteins. Subjects with NOTCH2 mutations demonstrated highly variable expressivity of the affected systems, as with JAG1 individuals. Liver involvement was universal in NOTCH2 probands and they had a similar prevalence of ophthalmologic and renal anomalies to JAG1 patients. There was a trend towards less cardiac involvement in the NOTCH2 group (60% vs 100% in JAG1). NOTCH2 (+) probands exhibited a significantly decreased penetrance of vertebral abnormalities (10%) and facial features (20%) when compared to the JAG1 (+) cohort.

CONCLUSIONS

This work confirms the importance of NOTCH2 as a second disease gene in ALGS and expands the repertoire of the NOTCH2 related disease phenotype.

Orthotopic liver transplantation for children with Alagille syndrome

AGS is an inherited disorder involving the liver, heart, eyes, face, and skeleton.

AIM

To determine the outcome of LT in children with AGS compared to those with BA.

METHODS

Children with AGS and BA who had a LT between 10/1987 and 5/2008 were identified from the UNOS database.

RESULTS

Of 11 467 children who received a liver transplant, 461 (4.0%) had AGS and 3056 (26.7%) had BA. One- and five-yr patient survival was significantly lower in patients with AGS in comparison with patients with BA (AGS; 82.9%, 78.4%, BA; 89.9%, 84%, respectively). Early death (<30 days from transplant) was significantly higher in AGS than in BA. One- and five-yr graft survival was significantly lower in AGS than in BA (AGS; 74.7%, 61.5%, BA; 81.6%, 70.0%, respectively). Death from graft failure, neurological, and cardiac complications was significantly higher in patients with AGS than in patients with BA. Serum creatinine at transplant, prior LT, and cold ischemic time >12 h were identified as risk factors for death.

CONCLUSION

Children with AGS were older at the time of LT and their one- and five-yr patient and graft survival were significantly lower compared to BA. Risk factors for poor outcome in AGS after LT were identified.

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.

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.

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.

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.

Alagille's syndrome associated with cystic renal disease

Although renal abnormalities have been described in children with Alagille's syndrome, cystic kidney disease has not often been documented, and then usually only at necropsy. Three children with Alagille's syndrome are described, in two of whom a unilateral multicystic dysplastic kidney was detected by prenatal ultrasound; in the other, a solitary cortical cyst was found later in childhood. All have normal renal function, growth, and liver synthetic function but continue to have clinical and biochemical signs of cholestasis. These cases show that unilateral cystic kidney disease with or without renal dysplasia may be associated with Alagille's syndrome, that the clinical course is not necessarily unfavourable, and that Alagille's syndrome should be included in the differential diagnosis of cystic kidney disorders associated with cholestatic liver disease. Patients with Alagille's syndrome should be evaluated by renal ultrasound.

Outcome of syndromic paucity of interlobular bile ducts (Alagille syndrome) with onset of cholestasis in infancy

OBJECTIVE

To determine the outcome, in index patients followed at an American Center, of syndromic paucity of interlobular bile ducts (sPILBD; Alagille syndrome), with onset of cholestasis in infancy.

DESIGN

Cohort.

SETTING

Regional referral center for infants and children with liver disease.

RESULTS

During the past 10 years, 26 unrelated children with sPILBD were identified. Fifteen (58%) are alive without liver transplantation at a median age of 12.1 years. Three (11%) died, all before 2 years of age. Eight patients (31%) underwent liver transplantation at a median age of 6.5 years; all eight are alive a median 5.4 years after transplantation. The most common factors contributing to the decision for transplantation were bone fractures, pruritus, and severe xanthoma. The predicted probability of reaching 19 years of age without transplantation is about 50%; however, with transplantation, the predicted probability of long-term survival is 87%. Of 26 patients 4 (15%) have had significant central nervous system disease, and two of them have died of intracranial hemorrhage. Of the four patients who underwent cholecystoportostomy or portoenterostomy, three required liver transplantation.

CONCLUSIONS

Children with sPILBD identified in infancy because of cholestasis have a 50% probability of long-term survival without liver transplantation, a worse prognosis than other follow-up studies have reported. In selected patients, liver transplantation provides the opportunity for long-term survival with improved quality of life. Patients with sPILBD are at risk of having intracranial hemorrhage.

Segregation analysis of Alagille syndrome

Alagille syndrome (AGS) is a well defined genetic disorder characterised by five major features. An autosomal dominant mode of transmission with reduced penetrance has been suggested by the analysis of a limited number of families. However there has been no statistical analysis. We report here the first segregation analysis of AGS, using 33 families collected through 43 probands. Segregation analysis of these families allowed us to conclude that AGS is transmitted as a dominant disorder with 94% penetrance and 15% of cases are sporadic. The expressivity of the phenotype was variable and 26 persons (15 parents and 11 sibs) were identified as presenting minor forms of the disease. These results are valuable for genetic counselling.

IgA nephritis in a patient with Alagille syndrome and a transplanted liver

Alagille syndrome (arteriohepatic dysplasia) is a major cause of intrahepatic cholestasis in infancy. The present report describes a patient with Alagille syndrome who presented with hematuria and IgA nephritis 7 years after an orthotopic liver transplantation and immunosuppression. This patient suggests that glomerular lipidosis is not an inherent feature of the Alagille syndrome, and that IgA nephritis may develop in spite of ongoing immunosuppressive treatment.

Infectious complications of pediatric liver transplantation

Twenty-five pediatric orthotopic liver transplantations (OLTs) performed in 22 patients at Sainte-Justine Hospital were reviewed for infections complications. One patient died within 12 hours posttransplantation and is excluded. The patients had an average age of 6.1 years (range, 1.25 to 19 years) and an average weight of 20.4 kg (range, 11 to 55 kg). Two patients (9%) were cytomegalovirus (CMV) seropositive and 9 of 19 patients (48%) were Epstein-Barr virus (EBV) seropositive preoperatively. Five of the donors (20%) were CMV seropositive. The most common indications for OLT were biliary atresia (8) and tyrosinemia (7). There were 4 deaths, for an overall mortality rate of 19%. In 3 patients, deaths were related to infection (CMV hepatitis and duodenitis with aortoduodenal fistula, adult respiratory distress syndrome [ARDS] with Streptococcus viridans pneumonia, Escherichia coli cholangitis with progressive hepatic failure). Fifteen patients (72%) had 41 major infections, most of them bacterial, during the first month posttransplantation. These include pneumonia (25%), line sepsis (17%), cholangitis (14%), and tracheitis (14%). There was only one major viral infection, a CMV hepatitis that occurred in the first month posttransplantation. Three patients had fungal infections (8%) associated with hepatic artery thrombosis and recurrent cholangitis. All three patients required retransplantation. There was only one protozoal infection (Pneumocystis carinii pneumonia) causing life-threatening respiratory failure, from which patient recovered without sequelae. Infection still remains a serious complication of OLT. Bacterial infection is common and is usually associated with technical complications. The low rate of CMV infection is related to low incidence of CMV in the donor pool and the minimal use of strong immunosuppressants.