Alagille Syndrome Mimicking Biliary Atresia in Early Infancy

Alagille Syndrome: Unraveling the Complexities of Genotype-Phenotype Relationships and Exploring Avenues for Improved Diagnosis and Treatment

Alagille syndrome (ALGS) is a rare genetic disorder caused by mutations in the JAG1 and NOTCH2 genes, leading to a wide range of clinical manifestations. This review explores the complex genetic and clinical landscape of ALGS, emphasizing the challenges in understanding genotype-phenotype relationships due to its rarity and the lack of suitable research models. The review projects a clinical overview of the disease, emphasizing the influence of potential gene modifiers on its clinical presentation and the lack of mechanistic studies for over 100 mutations identified in the last 24 years from various populations, representing a significant gap in our current knowledge and advocating for further exploration. The review addresses the diagnostic challenges posed by the variable expressivity and overlapping symptoms of ALGS. It summarizes current treatment options and discusses emerging approaches such as antisense oligonucleotides (ASOs) and gene therapies. Further, the need for improved diagnostic tools, a deeper understanding of the underlying mechanisms, and the development of targeted therapies are emphasized using zebrafish and mice models, as well as genome editing for variant analysis and stem cell organoid models for disease modeling and drug discovery. The importance of cohort-based studies in understanding the natural history and outcomes of ALGS in diverse populations is highlighted. The review concludes by emphasizing the need for multi-disciplinary collaborative research to address the challenges in ALGS diagnosis, prognosis, and treatment, particularly for underrepresented populations.

Genetics of biliary atresia: Approaches, pathological insights and challenges

Biliary atresia (BA) is a severe neonatal cholestatic disorder marked by fibro-obliteration of the extrahepatic and intrahepatic bile ducts. It is the most common cause of pediatric end-stage liver disease and the leading indication for liver transplantation in children. There is significant heterogeneity in the etiology, involving various genetic and environmental factors such as viral infection, immune dysregulation and genetic predisposition to defective hepatobiliary development. In this review, we discuss the strategies to uncover the genetic factors underlying BA and highlight their associated molecular and pathological mechanisms, as well as the challenges faced in this area of research.

Experience and Results of Liver Transplantation in Patients With Alagille Syndrome at Our Center

OBJECTIVES

Alagille syndrome is an autosomal recessive disorder with multisystemic involvement. Patients with Alagille syndrome have many accompanying anomalies such as atypical facial appearance, posterior embryotoxon, butterfly vertebra, cardiac anomalies, and biliary problems. Liver and heart complications can determine the mortality and morbidity of patients with Alagille syndrome. The scarcity of intrahepatic bile ducts leads to cholestatic liver damage. In the heart, although the disease most commonly causes peripheral pulmonary stenosis, patients can present with various structural heart diseases. These cardiac anomalies make intraoperative and postoperative management difficult in patients who need liver transplant. Here, we present 10 cases of liver transplant due to Alagille syndrome.

MATERIALS AND METHODS

From 1988 to the present, our center performed 724 liver transplants, with 366 being pediatric cases; among these, 10 were due to Alagille syndrome. We retrospectively examined patient morphological findings, cardiac pathology, and perioperative complications.

RESULTS

Average weight and age of patients were 11 kg and 4.9 years, respectively. Eight patients had atypical facial appearance, 5 had posterior embryotoxon, and 6 had butterfly vertebra. Portoenterostomy (Kasai procedure) was performed in 3 patients because of suspicion of early biliary atresia. Cardiac pathology was present in 8 patients, with peripheral pulmonary stenosis being the most common (present in 8 patients). One patient had cardiac catheterization, with right ventricular and pulmonary artery pressures measured at 110 and 37 mm Hg, respectively. Two patients required preoperative pulmonary angioplasty. Two patients had double superior vena cava. No complications occurred in any patient during the anhepatic phase with appropriate volume replacement. No patients had early mortality.

CONCLUSIONS

Cardiac anomalies should be identified in patients with Alagille syndrome to minimize complications before liver transplant. If necessary, cardiac catheterization should be performed for pulmonary stenosis. Peripheral pulmonary stenosis does not constitute an absolute contraindication to liver transplant.

Dual Deletion of Keap1 and Rbpjκ Genes in Liver Leads to Hepatomegaly and Hypercholesterolemia

The hepatic deletion of Rbpjκ (RbpjF/F::AlbCre) in the mouse leads to exhibition of the Alagille syndrome phenotype during early postnatal liver development with hyperlipidemia and cholestasis due to attenuated disruption of NOTCH signaling. Given the roles of NRF2 signaling in the regulation of lipid metabolism and bile ductal formation, it was anticipated that these symptoms could be alleviated by enhancing NRF2 signaling in the RbpjF/F::AlbCre mouse by hepatic deletion of Keap1 in compound Keap1F/F::RbpjF/F::AlbCre mice. Unexpectedly, these mice developed higher hepatic and plasma cholesterol levels with more severe cholestatic liver damage during the pre-weaning period than in the RbpjF/F::AlbCre mice. In addition, hypercholesterolemia and hepatic damage were sustained throughout the growth period unlike in the RbpjF/F::AlbCre mouse. These enhanced abnormalities in lipid metabolism appear to be due to NRF2-dependent changes in gene expression related to cholesterol synthetic and subsequent bile acid production pathways. Notably, the hepatic expression of Cyp1A7 and Abcb11 genes involved in bile acid homeostasis was significantly reduced in Keap1F/F::RbpjF/F::AlbCre compared to RbpjF/F::AlbCre mice. The accumulation of liver cholesterol and the weakened capacity for bile excretion during the 3 pre-weaning weeks in the Keap1F/F::RbpjF/F::AlbCre mice may aggravate hepatocellular damage level caused by both excessive cholesterol and residual bile acid toxicity in hepatocytes. These results indicate that a tuned balance of NOTCH and NRF2 signaling is of biological importance for early liver development after birth.

Clinical, Laboratory, Radiological, and Genetic Characteristics of Pediatric Patients with Alagille Syndrome

Background

Alagille syndrome (ALGS) is an autosomal dominant disease caused by JAG1 or NOTCH2 mutation. It is diagnosed by the presence of three out of five features: characteristic facies, posterior embryotoxon, peripheral pulmonary stenosis, vertebral defects, and interlobular bile duct paucity. This study aimed to review the prevalence, clinical presentations, diagnosis, treatment, and outcome of patients with ALGS.

Materials and Methods

This is a retrospective review of patients with ALGS at the Pediatric Department, Salmaniya Medical Complex, Bahrain, between August 1994 and October 2022. The diagnosis was based on clinical, laboratory, radiological, histopathological, and genetic findings.

Results

Five patients were found to have ALGS. The prevalence of ALGS in Bahrain was 1.04 patients per 100,000 (0.001%). Four were Bahraini and three were females. Median birth weight was 2.3 (2.3-2.5) kg. All patients presented at the time of birth with low birth weight, cholestatic jaundice, clay-colored stool, heart murmur, and dysmorphic facial features. All had congenital heart diseases, two had butterfly vertebrae, and one had posterior embryotoxon. All had elevated liver enzymes and normal abdominal ultrasound. Three had positive hepatobiliary iminodiacetic acid scan and one had bile duct paucity in liver biopsy. Three had intraoperative cholangiogram. Four were positive for JAG1 mutation. All received ursodeoxycholic acid and fat-soluble vitamins. Two required liver transplantation.

Conclusion

ALGS is a rare disorder in Bahrain. Diagnosis is challenging as the disease can be associated with or misdiagnosed as biliary atresia. Patients with ALGS are at high risk of morbidity either by unnecessary intraoperative cholangiogram or unavoidable liver transplantation.

COL3A1, CXCL8, VCAN, THBS2, and COL1A2 are correlated with the onset of biliary atresia

BACKGROUND

Biliary atresia (BA) is a devastating progressive fibro inflammatory disorder in infants. The exact etiology of BA is still unclear. This study aimed screen key genes potentially associated with the occurrence of BA.

METHODS

All BA data was obtained from GSE46960 dataset. The limma package in R language was used for differentially expressed gene (DEG) analyses. gene ontology and Kyoto encyclopedia of genes and genomes enrichment analysis were performed on the screened DEGs, using "clusterProfiler" package. protein-protein interaction network was built based on STRING Cytoscape software (Bethesda, Rockville, MD). The logistic regression model was constructed based on the selected DEGs.

RESULTS

There were totally 78 DEGs in BA samples compared with normal samples, which were significantly enriched in 200 biological process terms, 37 molecular function terms, 17 cellular component terms, and 18 Kyoto encyclopedia of genes and genomes pathways. Among which, the top 10 genes with the highest importance in protein-protein interaction network were selected. Subsequently, on the basis of the stepwise regression method and 5-fold cross-validation, the logistic regression model constructed based on COL3A1, CXCL8, VCAN, THBS2, and COL1A2 was finally evidenced to predict the BA sample relatively reliably.

CONCLUSIONS

In conclusion, COL3A1, CXCL8, VCAN, THBS2, and COL1A2 are potentially crucial genes in BA. The logistic regression model constructed based on them could predict the BA sample relatively reliably.

Anatomical patterns of biliary atresia including hepatic radicles at the porta hepatis influence short- and long-term prognoses

BACKGROUND/PURPOSE

The biliary atresia (BA) inflammatory process leads to various obstructive patterns of extrahepatic biliary trees. The significance of the various BA obstructive patterns is unclear. This study aimed to determine the relationship between the anatomical patterns of the biliary tract and short- and long-term prognoses in BA.

METHODS

Between 1989 and 2018, 3483 patients were registered in the Japanese Biliary Atresia Registry. For this study, we selected 2649 patients who underwent Kasai portoenterostomy (KP) between the ages of 31 and 90 days to eliminate the influence of age at KP as much as possible.

RESULTS

Regarding the main type, there were significant differences in the jaundice clearance rate (JCR; Type I: 67.9%, Type I-cyst: 79.4%, Type II: 74.5%, Type III: 60.9%; P < .0001) and the native liver survival rate (NLSR; P < .0001). In subgroups with hepatic radicles in Types I, II, and I-cyst, there was a significant difference in JCR (P = .0004) and NLSR (P = .0026). In subgroups with hepatic radicles in Type III, there was a significant difference in JCR (P = .0148) and NLSR (P = .0421).

CONCLUSIONS

Anatomical patterns of obstruction influenced short- and long-term prognoses in BA. These patterns were suggested to be prognostic factors following KP.

Two Novel Mutations in the JAG1 Gene in Pediatric Patients with Alagille Syndrome: The First Case Series in Czech Republic

Background: Alagille syndrome (ALGS) is a highly variable multisystem disorder inherited in an autosomal dominant pattern with incomplete penetration. The disorder is caused by mutations in the JAG1 gene, only rarely in the NOTCH2 gene, which gives rise to malformations in multiple organs. Bile duct paucity is the main characteristic feature of the disease. Methods: Molecular-genetic examination of genes JAG1 and NOTCH2 in four probands of Czech origin who complied with the diagnostic criteria of ALGS was performed using targeted next-generation sequencing of genes JAG1 and NOTCH2. Segregation of variants in a family was assessed by Sanger sequencing of parental DNA. Results: Mutations in the JAG1 gene were confirmed in all four probands. We identified two novel mutations: c.3189dupG and c.1913delG. Only in one case, the identified JAG1 mutation was de novo. None of the parents carrying JAG1 pathogenic mutation was diagnosed with ALGS. Conclusion: Diagnosis of the ALGS is complicated due to the absence of clear genotype-phenotype correlations and the extreme phenotypic variability in the patients even within the same family. This fact is of particular importance in connection to genetic counselling and prenatal genetic testing.

Genetic aspects of biliary atresia etiology

Biliary atresia (BA) is a cholestatic disorder of infancy that is fatal if untreated. Despite years of study the etiology of BA remains unknown. Three etiopathogenic mechanisms may be involved, such as immune dysregulation, environmental factors and genetic susceptibility. Genetic predisposition is being actively studied. Candidate genes associated with BA in certain populations, genes affecting the cholangiocyte cilia function, as well as genes involved in stress responses have been identified. However, the long-term follow-up of twins with BA suggests that genotype is not of paramount importance for the disease development. Both epigenetic patterns and postzygotic somatic mutations may contribute to etiology of the disease. Recently, some evidence is being accumulated on the possible genetic predisposition to certain outcome of Kasai portoenterostomy performed in patients with BA. However, the presence of a number of factors contributing to the development of the disease makes it difficult to identify the genetic markers.

Pediatric Liver Transplantation for Alagille Syndrome: Anesthetic Evaluation and Perioperative Management

BACKGROUND Alagille syndrome (AGS) is an autosomal dominant hereditary disorder characterized by identifiable abnormalities in the liver, heart, face, skeleton, and eyes. Recently, liver transplantation (LT) has been proposed as a therapeutic strategy for patients with AGS complicated by end-stage liver disease, but clinical experience in performing anesthesia in LT for AGS is still scarce. We aimed to summarize our preliminary experience in the anesthetic management of LT for AGS in this study. MATERIAL AND METHODS We reviewed the cases of 11 patients with AGS who underwent LT from September 2017 to April 2019. Preoperative multi-system comorbidities, intraoperative details, and postoperative outcomes were retrospectively collected and summarized. RESULTS Cardiopulmonary abnormalities were common (81.8%) in AGS patients before LT, and the most frequent comorbidity was pulmonary artery stenosis. After careful anesthetic evaluation and perioperative management, all patients survived during the perioperative period without significant cardiovascular complications. However, there was an unexpectedly high prevalence of surgical complications and re-operations in AGS patients compared to biliary atresia recipients (54.5% vs. 22.4%, P=0.031; and 45.5% vs. 15.3%, P=0.028, respectively). CONCLUSIONS Perioperative management of LT for AGS patients can be particularly challenging, requiring a full understanding of the pathophysiology, as well as a careful preoperative evaluation of the multi-system comorbidities. The high prevalence of postoperative surgical complications should be a matter of concern.

Outcomes of liver transplantation for Alagille syndrome after Kasai portoenterostomy: Alagille Syndrome with agenesis of extrahepatic bile ducts at porta hepatis

BACKGROUND

Alagille syndrome (ALGS) is an autosomal dominant disorder, characterized by a paucity of intrahepatic bile ducts, resulting in significant cholestasis, and peculiar extrahepatic features. Some ALGS patients show a considerable overlap with biliary atresia (BA), and they can undergo Kasai procedure. The purpose of this study is to show the manifestations of BA overlapped ALGS cases in our institution, and to compare the outcomes of ALGS patients following liver transplantation (LT) between those who previously underwent Kasai surgery (ALGS-Kasai group) and those who did not (ALGS-non-Kasai group).

METHODS

Medical records of ALGS patients who underwent LT in Kyoto University Hospital, Japan from January 1992 to March 2018 were analyzed. ALGS diagnosis was determined according to physical, radiologic, and histopathological findings.

RESULTS

Thirty-one patients were ascertained (ALGS-Kasai: 4 males and 5 females vs. ALGS-non-Kasai: 14 males and 8 females, p = 0.43). Of 31 ALGS patients, 96.8% of children had pulmonary artery stenosis, 54.8% showed facial features, 29% revealed skeletal anomalies and 9.7% demonstrated ocular anomalies. The age at LT was significantly younger in ALGS-Kasai than ALGS-non-Kasai group (1.47 [interquartile range (IQR), 0.75-1.92] vs. 5.1 [IQR, 1.4-9.29] years; p = 0.038). Overall patient survival did not significantly differ between ALGS-Kasai (88.9%) and ALGS-non-Kasai patients (86.4%) (p = 0.84). Furthermore, the 1-year, 5-year, and 10-year patient survival rates for ALGS-Kasai group were 100%, 88.9%, and 88.9%, respectively, whereas those for ALGS-non-Kasai group were 90.9%, 90.9%, and 86.4%, respectively, with p-values of 0.36, 0.90, and 0.84, respectively.

CONCLUSIONS

BA overlapped ALGS cases had neonatal progressive cholestasis which prompted Kasai procedure, and early liver dysfunction after Kasai led to performing LT. The ALGS-Kasai patients undergo LT at earlier ages than the ALGS-non-Kasai patients, however, overall patients' survival rates are similar between groups. Overall ALGS patients' survival rate after LT is considered high.

LEVELS OF EVIDENCE

Level III; Case-control study or Retrospective comparative study.

Genetics in biliary atresia

PURPOSE OF REVIEW

Biliary atresia is a poorly understood deadly disease. Genetic predisposition factors are suspected albeit not firmly established. This review summarizes recent evidence of genetic alterations in biliary atresia.

RECENT FINDINGS

Whole-genome association studies in biliary atresia patients identified four distinct predisposition loci with four different genes potentially involved in the disease occurrence. Variations in these genes were searched for, but none were found in patients with biliary atresia suggesting complex mechanisms.

SUMMARY

Despite decades since its description and decades of intensive researches, cause of biliary atresia disease remains enigmatic. The inheritance of biliary atresia is not Mendelian. Genetic predisposition factor is one of the explored fields to explain biliary atresia pathogenicity. Biliary atresia has been associated with several inborn syndromes, chromosome anomalies, and gene polymorphisms in specific populations. Four predisposition loci encompassing genes relevant to the disease have been identified, but no pathogenic variations were found in biliary atresia patients. Few reported cases of isolated biliary atresia manifestation in the context of known genetic diseases suggest coincidental findings. Alternatives to classic genetic alterations are proposed to explain genetic predisposition in biliary atresia including noncoding and epigenetic factors. Biliary atresia is most likely related to complex traits making its genetic exploration challenging.

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.

Outcomes of Alagille syndrome following the Kasai operation: a systematic review and meta-analysis

PURPOSE

Infants with Alagille syndrome (AGS) frequently develop neonatal cholestasis, and some AGS infants who suspected of biliary atresia subsequently undergo the Kasai operation with the diagnosis of biliary atresia. The aim of this study was to investigate the effect of the Kasai operation on liver and patient outcomes among AGS patients, using a meta-analysis.

METHODS

A systematic review and meta-analysis of studies describing the outcomes of AGS patients with/without the Kasai operation were conducted. The analyzed outcomes were liver transplantation, not living with the native liver, and mortality for any reason.

RESULTS

We identified 6 studies (394 AGS patients). All studies were retrospective cohort or case-control studies. The incidences of liver transplantation, not living with the native liver, and mortality were significantly higher in AGS patients who underwent the Kasai operation than in those who did not undergo the Kasai operation (odds ratio: 6.46, 95% CI 3.23-12.89, p < 0.00001; odds ratio: 25.88, 95% CI 2.83-236.84, p < 0.004; odds ratio: 15.05, 95% CI 2.70-83.93, p = 0.002, respectively).

CONCLUSION

The Kasai operation was associated with poor outcomes in AGS patients. It remains unclear if the Kasai operation directly deteriorates liver and patient outcomes in AGS patients.

Province-wide Biliary Atresia Home Screening Program in British Columbia: Evaluation of First 2 Years

BACKGROUND AND OBJECTIVES

Biliary atresia (BA), a rare newborn liver disease, is the leading cause of liver-related death in children. Early disease recognition and timely surgical Kasai hepatoportoenterostomy (KP) offers long-term survival without liver transplant. Universal BA screening in Taiwan using infant stool color cards (ISCCs) has proven effectiveness. We report our experience with infant stool color card (ISCC) BA screening in a province-wide program in British Columbia (BC). The objective of this study is to assess program performance and cost from launch April 1, 2014 to March 31, 2016.

METHODS

ISCCs distributed to families upon maternity ward discharge. Parents were instructed to monitor their infant's stool color for 1 month and contacted the screening center with concerns. The number of live births, ISCC distribution, BA cases, and costs were recorded. Cases with Program screen success had both acholic stool recognition (ISCC screen success) and timely referral for BA.

RESULTS

All 126 maternity units received ISCCs. Of 87,583 live births there were 6 BA cases. Of the 5 cases with ISCC Screen Success 3 had Program Screen Success. The median KP age in the program screen success and failure groups was 49 (42-52) and 116 (49-184) days, respectively. Program sensitivity was 50%, specificity 99%, positive predictive value 4%, and negative predictive value 99%. A random sample of 1054 charts at BC Children's Hospital found an ISCC distribution rate of 94%. After a phase-in period, the annual program cost was $30,033.82, and the ISCC cost per birth was $0.68.

CONCLUSIONS

The screening program has high specificity and distribution with low cost. Successful program case identification had earlier age at KP. Program modifications aim to improve sensitivity. Longer-term studies will determine program impact on health outcomes.

Variants Associated with Infantile Cholestatic Syndromes Detected in Extrahepatic Biliary Atresia by Whole Exome Studies: A 20-Case Series from Thailand

Biliary atresia (BA) is the most severe form of obstructive cholangiopathy occurring in infants. Definitive diagnosis of BA usually relies on operative findings together with supporting pathological patterns found in the extrahepatic bile duct. In infancy, overlapping clinical patterns of cholestasis can be found in other diseases including biliary hypoplasia and progressive familial intrahepatic cholestasis. In addition, BA has been reported as a phenotype in some rare genetic syndromes. Unlike BA, other cholangiopathic phenotypes have their own established genetic markers. In this study, we used these markers to look for other cholestasis entities in cases diagnosed with BA. DNA from 20 cases of BA, diagnosed by operative findings and histopathology, were subjected to a study of 19 genes associated with infantile cholestasis syndromes, using whole exome sequencing. Variant selection focused on those with allele frequencies in dbSNP150 of less than 0.01. All selected variants were verified by polymerase chain reaction-direct sequencing. Of the 20 cases studied, 13 rare variants were detected in 9 genes: 4 in JAG1 (Alagille syndrome), 2 in MYO5B (progressive familial intrahepatic cholestasis [PFIC] type 6), and one each in ABCC2 (Dubin-Johnson syndrome), ABCB11 (PFIC type 2), UG1A1 (Crigler-Najjar syndrome), MLL2 (Kabuki syndrome), RFX6 (Mitchell-Riley syndrome), ERCC4 (Fanconi anemia), and KCNH1 (Zimmermann-Laband syndrome). Genetic lesions associated with various cholestatic syndromes detected in cases diagnosed with BA raised the hypothesis that severe inflammatory cholangiopathy in BA may not be a distinct disease entity, but a shared pathology among several infantile cholestatic syndromes.

Combined genetic analyses can achieve efficient diagnostic yields for subjects with Alagille syndrome and incomplete Alagille syndrome

AIM

We evaluated combined genetic analyses with targeted next-generation sequencing (NGS), multiplex ligation probe amplification (MLPA) of Jagged1 (JAG1) genes and microarray comparative genomic hybridisation (CGH) in subjects with Alagille syndrome, incomplete clinical features of Alagille syndrome and biliary atresia.

METHODS

Subjects recruited from April 2013 to December 2015 underwent a targeted NGS analysis, including JAG1 and Notch homolog 2 (NOTCH2). If no mutations were detected in JAG1 or NOTCH2, or if copy number variations were suggested by the NGS analysis, we performed an MLPA analysis of JAG1. We also performed a microarray CGH analysis with whole-exon deletion detected by the MLPA analysis.

RESULTS

We analysed 30 subjects with Alagille syndrome, nine with incomplete Alagille syndrome and 17 with biliary atresia and detected pathogenic mutations in JAG1 or NOTCH2 in 24/30 subjects with Alagille syndrome and in 4/9 subjects with incomplete Alagille syndrome. No pathogenic mutations were detected in subjects with biliary atresia. The frequency of JAG1 mutations was as follows: single nucleotide variants (51.9%), small insertion or deletion (29.6%) and gross deletion (18.5%).

CONCLUSION

Combined genetic analyses achieved efficient diagnostic yields for subjects with Alagille syndrome and incomplete Alagille syndrome.

Diffusion Tensor Imaging for Evaluating Biliary Atresia in Infants and Neonates

BACKGROUND

Preliminary studies have shown that diffusion tensor imaging (DTI) is helpful in evaluating liver disorders. However, there is no published literature on the use of DTI in the diagnosis of biliary atresia (BA). This study aimed to investigate the diagnostic value of the liver average apparent diffusion coefficient (ADC) and fractional anisotropy (FA) measured using DTI for BA in neonates and infants.

METHODS

Fifty-nine patients with infant jaundice were included in this study. DTI was performed with b factors of 0 and 1000 s/mm2. Liver fibrosis in the BA group was determined and graded (F0, F1, F2, F3, F4) based on the pathological findings. Statistical analyses were performed to determine the diagnostic accuracy of DTI for BA.

RESULTS

The ADC value was significantly lower in the BA group [(1.262±0.127)×10-3 mm2/s] than in the non-BA group [(1.430±0.149)×10-3 mm2/s, (P<0.001)]. The area under the receiver operating characteristic curve was 0.805±0.058 (P<0.001) for ADC. With a cut-off value of 1.317×10-3 mm2/s, ADC achieved a sensitivity of 75% and a specificity of 81.5% for the differential diagnosis of BA and non-BA. In the BA group, the ADC value was significantly correlated with fibrotic stage. Further analysis showed that the ADC value of stage F0 was significantly higher than that of stages F1, F2, F3 and F4, whereas there were no significant differences among stages F1, F2, F3 and F4.

CONCLUSION

Hepatic ADC measured with DTI can be used as an adjunct to other noninvasive imaging methods in the differential diagnosis of BA and non-BA. ADC was helpful in detecting liver fibrosis but not in differentiating the fibrotic grades.