Clinical Features and Genetic Analysis of Pediatric Patients with Alagille Syndrome Presenting Initially with Liver Function Abnormalities

Cardiac complications caused by biliary diseases: A review of clinical manifestations, pathogenesis and treatment strategies of cholecardia syndrome

Gallbladder and biliary diseases (GBDs) are one of the most common digestive diseases. The connections between GBDs and several organs other than the liver have gradually surfaced accompanied by the changes in people's diet structure and the continuous improvement of medical diagnosis technology. Among them, cholecardia syndrome that takes the heart as the important target of GBDs complications has been paid close attention. However, there are still no systematic report about its corresponding clinical manifestations and pathogenesis. This review summarized recent reported types of cholecardia syndrome and found that arrhythmia, myocardial injury, acute coronary syndrome and heart failure are common in the general population. Besides, the clinical diagnosis rate of intrahepatic cholestasis of pregnancy (ICP) and Alagille syndrome associated with gene mutation is also increasing. Accordingly, the underlying pathogenesis including abnormal secretion of bile acid, gene mutation, translocation and deletion (JAG1, NOTCH2, ABCG5/8 and CYP7A1), nerve reflex and autonomic neuropathy were further revealed. Finally, the potential treatment measures and clinical medication represented by ursodeoxycholic acid were summarized to provide assistance for clinical diagnosis and treatment.

Different clinical and genetic features of Alagille patients with progressive disease versus a jaundice-free course

Background and Aim

Alagille syndrome (ALGS) is a multisystem disorder with variable clinical courses. This study investigated the clinical and genetic features of ALGS patients with different outcomes and analyzed the liver pathology at liver transplantation (LT) compared with that in biliary atresia (BA).

Methods

We report the clinical characteristics, outcomes, and genetic mutations of 25 children with ALGS followed for a median of 7.3 years. Patients were classified into (i) jaundice-free (JF) group (resolving jaundice after 2 years of age); (ii) progressive disease (PD) group (persistent jaundice or progressive cholestasis). In addition, we analyzed the explant liver in 10 ALGS patients compared with 20 age-matched BA patients at the time of LT.

Results

Nine patients (36%) in the JF group had a favorable outcome, with longer native liver survival than patients with PD (n = 16, P < 0.001). Fourteen of the PD group patients received LT or died. We identified 18 different JAG1 mutations in 22 patients. Three unrelated probands in the JF group had the same de novo mutation in JAG1, c.2122-2125delCAGT. Compared with BA children, ALGS patients had lower METAVIR scores in liver pathology, higher serum albumin levels, and lower weight-for-age z-scores when receiving LT.

Conclusion

One-third of ALGS patients had JF and a favorable course. Children with ALGS presenting with persistent jaundice beyond 2 years of age should be cautioned for poor prognosis. ALGS patients tend to have a lesser extent of cirrhosis, and more growth problems than BA patients at the time of LT.

Defining pathogenicity of NOTCH2 variants for diagnosis of Alagille syndrome type 2 using a large cohort of patients

BACKGROUND AND AIMS

Alagille syndrome (ALGS) type 2 caused by mutations in NOTCH2 has genotypic and phenotypic heterogeneity. Diagnosis in some atypical patients with isolated hepatic presentation could be missed.

METHODS

Using 2087 patients with paediatric liver manifestations, NOTCH2 allele frequencies, in-silico prediction, protein domains and clinical features were analysed to define the pathogenicity of NOTCH2 variants for diagnosis of ALGS type 2.

RESULTS

Among 2087 patients with paediatric liver manifestations, significantly more NOTCH2 variants were absent in gnomAD in patients with elevated γ-glutamyltransferase (GGT) (p = .041). Significantly more NOTCH2 variants which were absent in gnomAD were located in protein functional domains (p = .038). When missense variants were absent in gnomAD and predicted to be pathogenic by at least three out of seven in-silico tools, they were found to be significantly associated with liver manifestations with elevated GGT (p = .003). Comparing this to patients with likely benign (LB) variants, the patients with likely-pathogenic (LP) variants have significantly more liver manifestations with elevated GGT (p = .0001). Significantly more patients with LP variants had extra-hepatic phenotypes of ALGS compared with those patients with LB variants (p = .0004).

CONCLUSION

When NOTCH2 variants are absent in gnomAD, null variants and missense variants which were predicted to be pathogenic by at least three in-silico tools could be considered pathogenic in patients with high GGT chronic liver diseases.

Biliary Atresia: A Complex Hepatobiliary Disease with Variable Gene Involvement, Diagnostic Procedures, and Prognosis

The diagnosis of biliary atresia is still terrifying at the 3rd decade of the 21st century. In a department of neonatal intensive care unit, parents and physicians face a challenge with a jaundiced baby, who may or may not have a surgically correctable hepatopathy. The approach has been systematically evaluated, but the etiology remains ambiguous. The study of families with recurrent biliary atresia has been undertaken at a molecular level. The primary interest with this disease is to identify the etiology and change the treatment from symptomatic to curative. The occurrence of this obstructive cholangio-hepatopathy in well-known genetic syndromes has suggested just coincidental finding, but the reality can be more intriguing because some of these diseases may have some interaction with the development of the intrahepatic biliary system. Several genes have been investigated thoroughly, including ADD3 and GPC1 shifting the interest from viruses to genetics. In this review, the intriguing complexities of this hepatobiliary disease are highlighted.

Positive Association of the JAG1 rs1327235 Genotype with Coronary Artery Disease in Men, the Tampere Adult Population Cardiovascular Risk Study

Aims: The intronic single nucleotide polymorphism rs1327235 (A>G) close to the JAG gene has been implicated to be involved in blood pressure physiology in a genome-wide association study. We wanted to study whether it was associated with hypertension and coronary artery disease (CAD) in the Tampere adult population cardiovascular risk study. Materials and Methods: We analyzed a Finnish periodic health examination cohort of 191 men with diagnosed hypertension and 295 controls. Samples were genotyped for the JAG1 rs1327235 polymorphism using Competitive Allelic Specific PCR (KASP). The incidence of CAD was determined by self-report and the National Hospital Discharge Registry (HILMO). Results: There was no association between the JAG1 rs1327235 genotypes with hypertension at the age of 50 years. However, when the subjects were followed to the age of 60 years, those with the genotype GG had a higher prevalence of CAD (17.9%), compared with the A-allele (9.7%) (p = 0.036). When prevalence of CAD was adjusted by body mass index and total cholesterol, the OR for GG genotype was 2.19 (p = 0.029, confidence interval 1.084 - 4.429) compared with A-allele carriers. In addition, the GG genotype was associated with higher total cholesterol and low-density lipoprotein-cholesterol values, compared with the A-allele. Conclusions: Our findings suggest that the variations in JAG1 rs1327235 may be involved in CAD and cholesterol metabolism.

Alagille syndrome mutation update: Comprehensive overview of JAG1 and NOTCH2 mutation frequencies and insight into missense variant classification

Alagille syndrome is an autosomal dominant disease with a known molecular etiology of dysfunctional Notch signaling caused primarily by pathogenic variants in JAGGED1 (JAG1), but also by variants in NOTCH2. The majority of JAG1 variants result in loss of function, however disease has also been attributed to lesser understood missense variants. Conversely, the majority of NOTCH2 variants are missense, though fewer of these variants have been described. In addition, there is a small group of patients with a clear clinical phenotype in the absence of a pathogenic variant. Here, we catalog our single-center study, which includes 401 probands and 111 affected family members amassed over a 27-year period, to provide updated mutation frequencies in JAG1 and NOTCH2 as well as functional validation of nine missense variants. Combining our cohort of 86 novel JAG1 and three novel NOTCH2 variants with previously published data (totaling 713 variants), we present the most comprehensive pathogenic variant overview for Alagille syndrome. Using this data set, we developed new guidance to help with the classification of JAG1 missense variants. Finally, we report clinically consistent cases for which a molecular etiology has not been identified and discuss the potential for next generation sequencing methodologies in novel variant discovery.