Alagille syndrome and other hereditary causes of cholestasis

Targeted Next-Generation Sequencing in Diagnostic Approach to Monogenic Cholestatic Liver Disorders-Single-Center Experience

Objective: To evaluate the clinical utility of panel-based NGS in the diagnostic approach of monogenic cholestatic liver diseases. Study design: Patients with diagnosis of chronic cholestatic liver disease of an unknown etiology underwent NGS of targeted genes panel. Group 1 included five patients (prospectively recruited) hospitalized from January to December 2017 while group 2 included seventeen patients (retrospectively recruited) hospitalized from 2010 to 2017 presenting with low-GGT PFIC phenotype (group 2a, 11 patients) or indeterminant cholestatic liver cirrhosis (group 2b, 6 patients). Results: Among 22 patients enrolled into the study, 21 various pathogenic variants (including 11 novel) in 5 different genes (including ABCB11, ABCB4, TJP2, DGUOK, CYP27A1) were identified. The molecular confirmation was obtained in 15 out of 22 patients (68%). In group 1, two out of five patients presented with low-GGT cholestasis, and were diagnosed with BSEP deficiency. Out of three patients presenting with high-GGT cholestasis, one patient was diagnosed with PFIC-3, and the remaining two were not molecularly diagnosed. In group 2a, seven out of eleven patients, were diagnosed with BSEP deficiency and two with TJP-2 deficiency. In group 2b, three out of six patients were molecularly diagnosed; one with PFIC-3, one with CYP27A1 deficiency, and one with DGUOK deficiency. Conclusions: Panel-based NGS appears to be a very useful tool in diagnosis of monogenic cholestatic liver disorders in cases when extrahepatic causes have been primarily excluded. NGS presented the highest diagnosis rate to identify the molecular background of cholestatic liver diseases presenting with a low-GGT PFIC phenotype.

Alterations of Gut Microbiota in Cholestatic Infants and Their Correlation With Hepatic Function

Cholestasis is a major hepatic disease in infants, with increasing morbidity in recent years. Accumulating evidence has revealed that the gut microbiota (GM) is associated with liver diseases, such as non-alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. However, GM alterations in cholestatic infants and the correlation between the GM and hepatic functions remain uninvestigated. In this study, 43 cholestatic infants (IC group) and 37 healthy infants (H group) were enrolled to detect GM discrepancies using 16S rDNA analysis. The diversity in the bacterial community was significantly lower in the IC group than that in the H group (P = 0.013). After determining the top 10 abundant genera of microbes in the IC and H groups, we found that 13 of them were differentially enriched, including Bifidobacterium, Bacteroides, Streptococcus, Enterococcus, and Staphylococcus. As compared with the H group, the IC group had a more complex GM co-occurrence network featured by three core nodes: Phyllobacterium, Ruminococcus, and Anaerostipes. In addition, the positive correlation between Faecalibacterium and Erysipelatoclostridium (r = 0.689, P = 0.000, FDR = 0.009) was not observed in the IC patients. Using the GM composition, the cholestatic patients can be distinguished from healthy infants with high accuracy [areas under receiver operating curve (AUC) > 0.97], wherein Rothia, Eggerthella, Phyllobacterium, and Blautia are identified as valuable biomarkers. Using KEGG annotation, we identified 32 functional categories with significant difference in enrichment of the GM of IC patients, including IC-enriched functional categories that were related to lipid metabolism, biodegradation and metabolism of xenobiotics, and various diseases. In contrast, the number of functions associated with amino acid metabolism, nucleotide metabolism, and vitamins metabolism was reduced in the IC patients. We also identified significant correlation between GM composition and indicators of hepatic function. Megasphaera positively correlated with total bilirubin (r = 0.455, P = 0.002) and direct bilirubin (r = 0.441, P = 0.003), whereas γ-glutamyl transpeptidase was positively associated with Parasutterella (r = 0.466, P = 0.002) and negatively related to Streptococcus (r = -0.450, P = 0.003). This study describes the GM characteristics in the cholestatic infants, illustrates the association between the GM components and the hepatic function, and provides a solid theoretical basis for GM intervention for the treatment of infantile cholestasis.

Conjugated Hyperbilirubinemia in the Neonate and Young Infant

Cholestatic jaundice in the first few weeks of life may herald potentially life-threatening pathology. It is therefore incumbent upon the pediatric practitioner to have a high index of suspicion for severe disease when investigating jaundice in a young infant. This article outlines the epidemiology, pathophysiology, differential diagnosis, and diagnostic workup for both the most common and the most severe causes of cholestasis in the neonatal period.

An Atypical Presentation of Alagille Syndrome

Alagille syndrome is a multisystem disorder classically involving the liver, heart, vertebrae, facial features, and the eyes. In this case report, we document a case of Alagille syndrome with an atypical clinical and histopathologic presentation and subsequent identification of a novel JAG1 missense mutation. This case highlights that there may be both atypical clinical and pathologic findings in mutation-proven Alagille syndrome and that the diagnosis of Alagille syndrome should be considered in cases of ongoing bile duct damage in the setting of early-onset jaundice, cholestasis, hepatosplenomegaly, posterior embryotoxon in the eyes, and butterfly vertebrae.

The pathophysiology of human obstructive cholestasis is mimicked in cholestatic Gold Syrian hamsters

Obstructive cholestasis causes liver injury via accumulation of toxic bile acids (BAs). Therapeutic options for cholestatic liver disease are limited, partially because the available murine disease models lack translational value. Profiling of time-related changes following bile duct ligation (BDL) in Gold Syrian hamsters revealed a biochemical response similar to cholestatic patients in terms of BA pool composition, alterations in hepatocyte BA transport and signaling, suppression of BA production, and adapted BA metabolism. Hamsters tolerated cholestasis well for up to 28days and progressed relatively slowly to fibrotic liver injury. Hepatocellular necrosis was absent, which coincided with preserved intrahepatic energy levels and only mild oxidative stress. The histological response to cholestasis in hamsters was similar to the changes seen in 17 patients with prolonged obstructive cholestasis caused by cholangiocarcinoma. Hamsters moreover upregulated hepatic fibroblast growth factor 15 (Fgf15) expression in response to BDL, which is a cytoprotective adaptation to cholestasis that hitherto had only been documented in cholestatic human livers. Hamster models should therefore be added to the repertoire of animal models used to study the pathophysiology of cholestatic liver disease.

Biliary bile acids in hepatobiliary injury - What is the link?

The main trigger for liver injury in acquired cholestatic liver disease remains unclear. However, the accumulation of bile acids (BAs) undoubtedly plays a role. Recent progress in deciphering the pathomechanisms of inborn cholestatic liver diseases, decoding mechanisms of BA-induced cell death, and generating modern BA-derived drugs has improved the understanding of the regulation of BA synthesis and transport. Now is the appropriate time to reassess current knowledge about the specific role of BAs in hepatobiliary injury.

Diagnostic considerations for cholestatic liver disease

Cholestatic liver disease results from insufficient bile synthesis, secretion and/or flow through the biliary tract. Common presenting features include fatigue, pruritus, and cholestatic liver enzyme abnormalities wherein elevations of serum alkaline phosphatase and gamma-glutamyltransferases levels exceed those of alanine and aspartate aminotransferases. With prolonged cholestasis, fat soluble vitamin deficiencies, fibrosis, cirrhosis, and, on occasion, carcinoma of the biliary tract or liver can occur. Once mechanical obstruction to bile flow has been ruled out, the majority of causes can be classified as immune-mediated, infectious, or miscellaneous. Because specific therapeutic options are increasing for many causes of cholestasis, an accurate diagnosis is an important first step towards treatment. Thus, this review focuses on the diagnostic features of non-mechanical causes of cholestasis.

Heart Disease and the Liver: Pathologic Evaluation

Liver injury due to acute and chronic heart failure has long been recognized. This article discusses the concepts of acute cardiogenic liver injury (ACLI) and cardiac or congestive hepatopathy (CH) along with their clinical manifestations and sequelae. Histologically, ACLI manifests as centrilobular hepatocellular necrosis, whereas CH is associated with centrilobular hepatocyte atrophy, dilated sinusoids, and perisinusoidal fibrosis, progressing to bridging fibrosis and ultimately cirrhosis. ACLI is associated with marked increases in aminotransferase levels, whereas CH is associated with a cholestatic pattern of laboratory tests. Certain cardiac medications have also been implicated as a cause of liver fibrosis.

Individualized Medicine in Gastroenterology and Hepatology

After the completion of the Human Genome Project, there has been an acceleration in methodologies on sequencing nucleic acids (DNA and RNA) at a high precision and with ever-decreasing turnaround time and cost. Collectively, these approaches are termed next-generation sequencing and are already affecting the transformation of medical practice. In this symposium article, we highlight the current knowledge of the genetics of selected gastrointestinal tract and liver diseases, namely, inflammatory bowel disease, hereditary cholestatic liver disease, and familial colon cancer syndromes. In addition, we provide a stepwise approach to use next-generation sequencing methodologies for clinical practice with the goal to improve the diagnosis as well as management of and/or therapy of the chosen digestive diseases. This early experience of applying next-generation sequencing in the practice of gastroenterology and hepatology will delineate future best practices in the field, ultimately for the benefit of our patients.

Giant hepatic regenerative nodules in Alagille syndrome

BACKGROUND

Children with Alagille syndrome undergo surveillance radiologic examinations as they are at risk for developing cirrhosis and hepatocellular carcinoma. There is limited literature on the imaging of liver masses in Alagille syndrome. We report the ultrasound (US) and magnetic resonance imaging (MRI) appearances of incidental benign giant hepatic regenerative nodules in this population.

OBJECTIVE

To describe the imaging findings of giant regenerative nodules in patients with Alagille syndrome.

MATERIALS AND METHODS

A retrospective search of the hospital database was performed to find all cases of hepatic masses in patients with Alagille syndrome during a 10-year period. Imaging, clinical charts, laboratory data and available pathology were reviewed and analyzed and summarized for each patient.

RESULTS

Twenty of 45 patients with confirmed Alagille syndrome had imaging studies. Of those, we identified six with giant focal liver masses. All six patients had large central hepatic masses that were remarkably similar on US and MRI, in addition to having features of cirrhosis. In each case, the mass was located in hepatic segment VIII and imaging showed the mass splaying the main portal venous branches at the hepatic hilum, as well as smaller portal and hepatic venous branches coursing through them. On MRI, signal intensity of the mass was isointense to liver on T1-weighted sequences in four of six patients, but hyperintense on T1 in two of six patients. In all six cases, the mass was hypointense on T2- weighted sequences. The mass post-contrast was isointense to adjacent liver in all phases in five the cases. Five out of six patients had pathological correlation demonstrating preserved ductal architecture confirming the final diagnosis of a regenerative nodule.

CONCLUSION

Giant hepatic regenerative nodules with characteristic US and MR features can occur in patients with Alagille syndrome with underlying cirrhosis. Recognizing these lesions as benign giant hepatic regenerative nodules should, thereby, mitigate any need for intervention.

Guideline for the Evaluation of Cholestatic Jaundice in Infants: Joint Recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition

Cholestatic jaundice in infancy affects approximately 1 in every 2500 term infants and is infrequently recognized by primary providers in the setting of physiologic jaundice. Cholestatic jaundice is always pathologic and indicates hepatobiliary dysfunction. Early detection by the primary care physician and timely referrals to the pediatric gastroenterologist/hepatologist are important contributors to optimal treatment and prognosis. The most common causes of cholestatic jaundice in the first months of life are biliary atresia (25%-40%) followed by an expanding list of monogenic disorders (25%), along with many unknown or multifactorial (eg, parenteral nutrition-related) causes, each of which may have time-sensitive and distinct treatment plans. Thus, these guidelines can have an essential role for the evaluation of neonatal cholestasis to optimize care. The recommendations from this clinical practice guideline are based upon review and analysis of published literature and the combined experience of the authors. The committee recommends that any infant noted to be jaundiced after 2 weeks of age be evaluated for cholestasis with measurement of total and direct serum bilirubin, and that an elevated serum direct bilirubin level (direct bilirubin levels >1.0 mg/dL or >17 μmol/L) warrants timely consideration for evaluation and referral to a pediatric gastroenterologist or hepatologist. Of note, current differential diagnostic plans now incorporate consideration of modern broad-based next-generation DNA sequencing technologies in the proper clinical context. These recommendations are a general guideline and are not intended as a substitute for clinical judgment or as a protocol for the care of all infants with cholestasis. Broad implementation of these recommendations is expected to reduce the time to the diagnosis of pediatric liver diseases, including biliary atresia, leading to improved outcomes.

Transition of gastroenterological patients from paediatric to adult care: A position statement by the Italian Societies of Gastroenterology

In 2013, four Italian Gastroenterological Societies (the Italian Society of Paediatric Gastroenterology, Hepatology and Nutrition, the Italian Society of Hospital Gastroenterologists and Endoscopists, the Italian Society of Endoscopy, and the Italian Society of Gastroenterology) formed a joint panel of experts with the aim of preparing an official statement on transition medicine in Gastroenterology. The transition of adolescents from paediatric to adult care is a crucial moment in managing chronic diseases such as celiac disease, inflammatory bowel disease, liver disease and liver transplantation. Improved medical treatment and availability of new drugs and surgical techniques have improved the prognosis of many paediatric disorders, prolonging survival, thus making the transition to adulthood possible and necessary. An inappropriate transition or the incomplete transmission of data from the paediatrician to the adult Gastroenterologist can dramatically decrease compliance to treatment and prognosis of a young patient, particularly in the case of severe disorders. For these reasons, the Italian gastroenterological societies decided to develop an official shared transition protocol. The resulting document discusses the factors influencing the transition process and highlights the main points to accomplish to optimize compliance and prognosis of gastroenterological patients during the difficult transition from childhood to adolescence and adulthood.

Novel mutations in the SLC25A13 gene in a patient with NICCD and severe manifestations

Neonatal intrahepatic cholestatic due to citrin deficiency (NICCD) is an autosomal recessive disorder caused by mutations in the SLC25A13 gene and characterized by neonatal/infantile-onset cholestatic hepatitis syndrome associated with conjugated hyperbilirubinemia and multiple aminoacidemias. We report the case of a Chinese female patient with NICCD disease who manifested prominent clinical features. The patient was diagnosed with NICCD based on cholestasis, aminoacidemia, and hypoproteinemia. She exhibited extreme aminoacidemia, coagulation disorders and untypical myocardial damage, which are rare in other NICCD patients genetically confirmed by us. This myocardial damage observed in obstructive jaundice could be caused by both hyperbilirubinemia and redundant blood bile acids. Screening the SLC25A13 gene revealed that this patient was compound heterozygous harboring two novel mutations, the c. 640C>T (p. Gln214X) in exon 7 and the c. 1709_1710insA (p. Ile570fs573X) in exon 16. Both mutations cause a premature stop codon and thereby truncated peptide or nonsense-mediated with loss of natural function accordingly. In conclusion, extremely manifested clinical features, including significant hyperbilirubinemia, multiple aminoacidemia, hypoproteinemia, coagulation disorders, and myocardial damage related to redundant blood bilirubin and bile acids, were observed in a NICCD patients with two novel mutations.

Statin use in Australian children: a retrospective audit of four pediatric hospitals

AIM

The aim of this study was to perform an audit of the use of statins in Australian pediatric hospitals.

METHODS

A retrospective audit of patients prescribed statins during a visit to a pediatric hospital, as in- or outpatients, was performed in four major children's hospitals in three Australian states. Patients were identified through hospital pharmacy dispensing records. Statin use (dose, type) as well as medical history was recorded.

RESULTS

A total of 157 patients under the age of 18 were included in the audit. The most common reasons for being prescribed a statin included history of organ transplantation, renal disease and familial hypercholesterolemia (FH). Four statins were prescribed: atorvastatin (n = 77), pravastatin (n = 45), simvastatin (n = 25) and rosuvastatin (n = 10). All statins, apart from rosuvastatin, were used in very young children (1-7 years old). Polypharmacy was common in these patients, including combinations with calcineurin inhibitors and diltiazem, which can increase systemic statin exposure. A small number of very young children were prescribed high doses of statin, based on mg/kg dosing.

CONCLUSIONS

Statins were prescribed to children younger than suggested by current Australian guidelines, with atorvastatin being the preferred statin of choice. Long-term safety studies on the use of statins in children have only included FH patients so far, who are generally healthy besides their raised lipid levels. Further long-term safety studies are needed to include the more vulnerable transplant and renal patients, identified in this audit as being prescribed statins. This can help formulate guidelines for the safest possible use of this class of drugs in the pediatric setting, including the possibility of weight-based recommendations for younger children.