Whole-exome sequencing for genetic diagnosis of idiopathic liver injury in children.

Genome-wide approaches, such as whole-exome sequencing (WES), are widely used to decipher the genetic mechanisms underlying inter-individual variability in disease susceptibility. We aimed to dissect inborn monogenic determinants of idiopathic liver injury in otherwise healthy children. We thus performed WES for 20 patients presented with paediatric-onset recurrent elevated transaminases (rELT) or acute liver failure (ALF) of unknown aetiology. A stringent variant screening was undertaken on a manually-curated panel of 380 genes predisposing to inherited human diseases with hepatobiliary involvement in the OMIM database. We identified rare nonsynonymous variants in nine genes in six patients (five rELT and one ALF). We next performed a case-level evaluation to assess the causal concordance between the gene mutated and clinical symptoms of the affected patient. A genetic diagnosis was confirmed in four rELT patients (40%), among whom two carried novel mutations in ACOX2 or PYGL, and two had previously-reported morbid variants in ABCB4 or PHKA2. We also detected rare variants with uncertain clinical significance in CDAN1, JAG1, PCK2, SLC27A5 or VPS33B in rELT or ALF patients. In conclusion, implementation of WES improves diagnostic yield and enables precision management in paediatric cases of liver injury with unknown aetiology, in particular recurrent hypertransaminasemia.

Food protein-induced allergic proctocolitis in infants is associated with low serum levels of macrophage inflammatory protein-3a.

BACKGROUND: Food protein-induced allergic proctocolitis (FPIAP) is a nonimmunoglobulin (IgE)-mediated food hypersensitivity and the exact mechanisms that cause FPIAP are unknown. Chemokines play crucial roles in the development of allergic diseases. OBJECTIVE: To examine serum levels of a group of chemokines in infants with FPIAP. METHODS: In 67 infants with FPIAP and 65 healthy infants, we measured serum levels of mucosa-associated epithelial chemokine (MEC/CCL28), thymus-expressed chemokine (TECK/CCL25), CX3CL1 and macrophage inflammatory protein (MIP)-3a/CCL20. RESULTS: Infants with FPIAP had a lower median value of MIP3a/CCL20 than healthy infants [0.7 (0-222) vs. 4 (0-249) pg/mL, respectively] (p < 0.001). Infants with MIP3a/CCL20 levels ≤0.95 pg/mL have 13.93 times more risk of developing FPIAP than infants with MIP3a/CCL20 levels >0.95 pg/mL. Serum MEC/CCL28, TECK/CCL25, and CX3CL1 levels were similar between the infants with FPIAP and the control group. CONCLUSION: MIP3a/CCL20 serum levels were reduced in infants with FPIAP compared with healthy controls. Whether this finding has a role in pathogenesis remains to be determined.

Evaluation of Vitamin D Levels in Children With Liver Transplant.

OBJECTIVES: Vitamin D deficiency is common in pediatric chronic liver disease despite oral replacement. We evaluated vitamin D deficiency before and after liver transplant and the relationship between posttransplant and pretransplant vitamin D deficiency and graft rejection. MATERIALS AND METHODS: Pediatric recipients with chronic liver disease (N =138) were divided into 4 groups: cholestatic liver diseases, cirrhosis, metabolic disorders, and acute liver failure. Pretransplant and posttransplant vitamin D levels, liver function tests, Pediatric End-Stage Liver Disease scores, rejection activity index scores by graft liver biopsy, and posttransplant patient survival were recorded. RESULTS: There were 62 (45%) female and 76 (55%) male participants (mean transplant age, 6.1 ± 5.6 years). Pretransplant mean available vitamin D of 90 patients was 25.2 ± 20.9 ng/mL, with 36 (40%) within reference range. Posttransplant level for 109 patients was 27.3 ± 18 ng/mL, with 64 (58.7%) within reference range. Pretransplant and posttransplant levels were available for 61 patients, and mean pretransplant levels were lower than posttransplant levels (23.7 ± 19.3 vs 28.3 ± 16.9 ng/mL; P = .01). Patients with cholestatic liver disease had lower pretransplant vitamin D levels (P = .04), which disappeared after transplant. Pretransplant vitamin D levels were positively correlated with serum albumin levels (r = 0.20) in all patients and negatively correlated with total/direct bilirubin (r = 0.29 and r = -0.30) in those with liver diseases and cirrhosis. No correlations were found between pretransplant vitamin D levels and Pediatric End-Stage Liver Disease scores, rejection activity index scores, and posttransplant mortality. CONCLUSIONS: Vitamin D deficiency is prevalent in pediatric chronic liver disease before and after transplant, especially for cholestatic liver diseases. However, no association between vitamin D levels and liver graft rejection or patient survival was noted. We recommend close monitoring and individualized vitamin D supplementation before and after liver transplant.

HMGB1 is related to disease activity in children with celiac disease.

INTRODUCTION: We aim to evaluate of the relationship between high mobility gene box-1 (HMGB1) levels and clinical, laboratory and histopathological findings at diagnosis and in remission in children with Celiac Disease (CD). MATERIAL AND METHODS: The study included 36 celiac patients at diagnosis, 36 celiac patients in remission, and 36 healthy controls. Patients with intestinal pathologies other than CD, and accompanying inflammatory and/or autoimmune diseases were excluded. Relationship between HMGB1 levels and clinical, laboratory and histopathological findings were evaluated. RESULTS: A total of 72 celiac patients [36 (18 girls, 18 boys, mean age 9.41±3.9 years) in group 1 and 36 (18 girls, 18 boys, mean age 9.91±3.36 years) in group 2] and 36 healthy controls in group 3 (19 girls, 17 boys, mean age 9.56±4 years) were included. The HMGB1 level was significantly higher in group 1 compared to group 2 and group 3 [36.63 (17.98-54.72) ng/ml vs 20.31 (16.89-29.79) ng/ml, p = 0.028 and 36.63 (17.98-54.72) ng/ml vs 20.38 (17.54-24.53) ng/ml p = 0.012, respectively]. A serum HMGB-1 level of 26.553 ng/ml was found to be a cut-off value for the CD with 61% sensitivity, 83% specificity, 78% positive predictive value, and 68% negative predictive value. Higher HMGB1 values were seen in patients with intestinal findings, anemia, anti-tissue transglutaminase IgA levels that were greater than 10 times upper limit of normal, and patients with a higher degree of atrophy as classified by Marsh-Oberhuber. CONCLUSIONS: In conclusion, it was thought that HMGB-1 might be a marker that reflects the severity of atrophy at the time of diagnosis and could be used to control dietary compliance in the follow-up. However, there is need for larger population studies in order to evaluate its value as a serological marker for the diagnosis and follow-up of CD and to find a more reliable cut-off value.

Prevalence of Infections in Infants Within the First 6 Months of Liver Transplant.

OBJECTIVES: In this retrospective study, we aimed to determine the most common infectious agents in infants within the first 6 months of liver transplant. MATERIALS AND METHODS: Thirty-four infant patients with median age of 8 months (range, 4-12 mo) at the time of liver transplant were retrospectively evaluated. We evaluated causative organisms in bloodstream cultures and in subclavian catheter, urine, and intra-abdominal drainage fluid cultures. We also evaluated Epstein-Barr and cytomegalovirus infections by polymerase chain reaction in all recipients. RESULTS: The most common isolated bacteria from the bloodstream were Klebsiella pneumoniae, Staphylococcus epidermidis, and Enterococcus faecium. Staphylococcus epidermidis was the most common isolated bacteria from subclavian catheter cultures. Klebsiella pneumoniae was the most common bacteria isolated from intra-abdominal drainage fluid. Only 1 recipient had cytomegalovirus infection during this period. CONCLUSIONS: Our study showed a high incidence of Klebsiella pneumoniae infections in infants after liver transplant. New prophylactic antibiotic strategies can be promoted to prevent Klebsiella pneumoniae infections in infants.

Incidence, clinical features, and outcomes of food allergy in children who underwent liver transplant: 16-year experience.

Food allergies often develop after liver transplant, especially in young children. However, data are scarce on clinical characteristics and patient outcomes. When we evaluated our pediatric liver transplant patients over a 16-year period, food allergy incidence was 8% (19/236 patients). All patients with food allergies were <18 months old, with incidence in this age group of 19.2% (19/99). Two patients had a single food and 17 had multiple food allergies. Five patients showed only non-IgE-mediated food allergies. Eggs, milk, nuts, and wheat were the most common allergens. Presenting symptoms included diarrhea, flushing, angioedema attacks, wheezing/chronic cough, and vomiting. Seven patients had EBV, and two patients had CMV infections at time of food allergy diagnosis. Twelve patients had eosinophilia. Seven patients (36.8%) were able to regain tolerance to all food allergens. However, one patient with single nut allergy and three with multiple food allergies were still on allergen-eliminated diets. Eight patients with multiple food allergies gained tolerance to some of the food allergens. In conclusion, food allergies in our patients were mainly against multiple foods and IgE mediated. Infections like EBV and CMV may play a role in food allergies after liver transplant, especially in pretransplant-naive patients.

Liver Transplant in a Patient With Hemophagocytic Lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis is a rare and life-threatening systemic disease that can cause hepatic infiltration and present as acute liver failure. Here, we report a case of a 3-year-old pediatric patient who presented with acute liver failure and hepatic encephalopathy secondary to hemophagocytic lymphohistiocytosis. She had left lateral segment liver transplant from her father. After 27 months, she had bone marrow transplant from her sister. At the time of reporting (36 months after liver transplant), she showed normal liver function and blood peripheral counts. We found that liver transplant can be a curative treatment for this type of rare disorder, not only to improve the quality of life but also to prolong survival.

Liver Cirrhosis in a Patient with Crigler Najjar Syndrome.

INTRODUCTION: Crigler Najjar (CN) disease is a genetic disorder which results in increased unconjugated bilirubin level. Liver parenchyma was previously considered structurally normal. Recent reports describe significant fibrosis in the liver parenchyma of patients with CN syndrome. CASE REPORT: We present a patient with persistent unconjugated hyperbilirubinemia, clinically diagnosed as CN-2, with a UGT1 A1 p. H39D (c.115C > G) (His → Asp) mutation. She required hepatic transplantation at the age of 17.5 years for biliary cirrhosis. Explanted liver histopathology revealed regenerative cirrhotic nodules with dilated bile ducts filled with bile plugs. CONCLUSION: CN can develop significant hepatic fibrosis/cirrhosis requiring liver transplantation.

A Case of Shwachman-Diamond Syndrome who Presented with Hypotonia.

We present a patient with failure to thrive and severe hypotonia, who was initially suspected of having a neurometabolic disease but later diagnosed as Shwachman-Diamond syndrome (SDS), which was genetically confirmed. SDS is a multisystemic disease, which is characterized by exocrine pancreatic deficiency, bone marrow dysfunction with increased risk for malignant transformation, and skeletal abnormalities. It should be included in differential diagnosis of patients with failure to thrive and unexplained neurodevelopmental delay with neutropenia.

A single-center experience of post-transplant lymphoproliferative disorder (PTLD) cases after pediatric liver transplantation: Incidence, outcomes, and association with food allergy.

BACKGROUND/AIMS: We evaluated our 16-year single-center experience of pediatric post-transplant lymphoproliferative disorder (PTLD) cases who underwent liver transplantation between 2001 and 2017. MATERIALS AND METHODS: Of the 236 pediatric patients who underwent liver transplantation between 2001 and 2017, the clinical and laboratory data of eight patients diagnosed with PTLD were reviewed. The pre-transplant Epstein-Barr virus (EBV) status of 172 patients was also recorded. RESULTS: The total incidence of PTLD was 3.4%. The incidence of PTLD was 10% in pre-transplant EBV immunoglobulin G (IgG)-seronegative patients and 0.8% in pre-transplant EBV IgG-seropositive patients. The mean age of the patients at liver transplantation was 2.71±3.21 years, and four patients were aged below 1 year at the time of transplantation. PTLD was diagnosed at 21.81±18.1 months after transplantation. The primary site of involvement was variable among patients: peripheral and mediastinal lymph nodes, stomach and intestine, transplanted graft, bone marrow, and nasopharynx. The eosinophil count varied greatly among patients, with a mean value of 524.62±679/mm3. Three patients had a food allergy and were administered an elimination diet at the time of PTLD diagnosis. Six patients had PTLD of B-cell origin. One patient died due to neutropenic sepsis during chemotherapy, whereas seven patients were followed up in full remission for 7.75±4 years. CONCLUSION: PTLD is a life-threatening complication of solid-organ transplantation with a heterogeneous clinical spectrum. Food allergy had a close association with PTLD. A close follow-up of patients with risk factors and an early diagnosis with appropriate treatment may lead to a better outcome.

Intestinal Failure and Aberrant Lipid Metabolism in Patients With DGAT1 Deficiency.

BACKGROUND & AIMS: Congenital diarrheal disorders are rare inherited intestinal disorders characterized by intractable, sometimes life-threatening, diarrhea and nutrient malabsorption; some have been associated with mutations in diacylglycerol-acyltransferase 1 (DGAT1), which catalyzes formation of triacylglycerol from diacylglycerol and acyl-CoA. We investigated the mechanisms by which DGAT1 deficiency contributes to intestinal failure using patient-derived organoids. METHODS: We collected blood samples from 10 patients, from 6 unrelated pedigrees, who presented with early-onset severe diarrhea and/or vomiting, hypoalbuminemia, and/or (fatal) protein-losing enteropathy with intestinal failure; we performed next-generation sequencing analysis of DNA from 8 patients. Organoids were generated from duodenal biopsies from 3 patients and 3 healthy individuals (controls). Caco-2 cells and patient-derived dermal fibroblasts were transfected or transduced with vectors that express full-length or mutant forms of DGAT1 or full-length DGAT2. We performed CRISPR/Cas9-guided disruption of DGAT1 in control intestinal organoids. Cells and organoids were analyzed by immunoblot, immunofluorescence, flow cytometry, chromatography, quantitative real-time polymerase chain reaction, and for the activity of caspases 3 and 7. RESULTS: In the 10 patients, we identified 5 bi-allelic loss-of-function mutations in DGAT1. In patient-derived fibroblasts and organoids, the mutations reduced expression of DGAT1 protein and altered triacylglycerol metabolism, resulting in decreased lipid droplet formation after oleic acid addition. Expression of full-length DGAT2 in patient-derived fibroblasts restored formation of lipid droplets. Organoids derived from patients with DGAT1 mutations were more susceptible to lipid-induced cell death than control organoids. CONCLUSIONS: We identified a large cohort of patients with congenital diarrheal disorders with mutations in DGAT1 that reduced expression of its product; dermal fibroblasts and intestinal organoids derived from these patients had altered lipid metabolism and were susceptible to lipid-induced cell death. Expression of full-length wildtype DGAT1 or DGAT2 restored normal lipid metabolism in these cells. These findings indicate the importance of DGAT1 in fat metabolism and lipotoxicity in the intestinal epithelium. A fat-free diet might serve as the first line of therapy for patients with reduced DGAT1 expression. It is important to identify genetic variants associated with congenital diarrheal disorders for proper diagnosis and selection of treatment strategies.

Solid Liver Lesions in an Infant With Neonatal Cholestasis: Is it Always Malignant?

In this report we describe a patient with neonatal cholestasis who was found to have a liver lesion with suspicious imaging features, although ultimately it was histologically proved to be a pseudotumor. We discuss the characteristic features and imaging findings of macroregenerative nodules of the liver.

CD55 Deficiency, Early-Onset Protein-Losing Enteropathy, and Thrombosis.

BACKGROUND: Studies of monogenic gastrointestinal diseases have revealed molecular pathways critical to gut homeostasis and enabled the development of targeted therapies. METHODS: We studied 11 patients with abdominal pain and diarrhea caused by early-onset protein-losing enteropathy with primary intestinal lymphangiectasia, edema due to hypoproteinemia, malabsorption, and less frequently, bowel inflammation, recurrent infections, and angiopathic thromboembolic disease; the disorder followed an autosomal recessive pattern of inheritance. Whole-exome sequencing was performed to identify gene variants. We evaluated the function of CD55 in patients' cells, which we confirmed by means of exogenous induction of expression of CD55. RESULTS: We identified homozygous loss-of-function mutations in the gene encoding CD55 (decay-accelerating factor), which lead to loss of protein expression. Patients' T lymphocytes showed increased complement activation causing surface deposition of complement and the generation of soluble C5a. Costimulatory function and cytokine modulation by CD55 were defective. Genetic reconstitution of CD55 or treatment with a complement-inhibitory therapeutic antibody reversed abnormal complement activation. CONCLUSIONS: CD55 deficiency with hyperactivation of complement, angiopathic thrombosis, and protein-losing enteropathy (the CHAPLE syndrome) is caused by abnormal complement activation due to biallelic loss-of-function mutations in CD55. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

Etiologies, outcomes, and prognostic factors of pediatric acute liver failure: A single center's experience in Turkey.

BACKGROUND/AIMS: Our aim was to determine the etiologies, outcomes, and prognostic indicators in children with acute liver failure. MATERIALS AND METHODS: Ninety-one patients who were followed for pediatric acute liver failure (PALF) over a 15-year period were included. Patients who survived with supportive therapy were designated as Group 1, while those who died or underwent liver transplantation were designated as Group 2. RESULTS: There were 37 (40.6%) patients in Group 1 (spontaneous recovery) and 54 (59.4%) patients in Group 2. Thirty-two patients (35.2%) underwent liver transplantation. Infectious and indeterminate causes were the most common etiologies (33% each). Among the infectious causes, hepatitis A (76%) was the most frequent. Hepatic encephalopathy grade 3-4 on admission and during follow-up and high Pediatric Risk of Mortality (PRISM) and Pediatric End-Stage Liver Disease (PELD) scores within the first 24 h were related with a poor prognosis. Group 2 had a more prolonged prothrombin time, higher international normalized ratio, more prolonged activated partial thromboplastin time (aPTT), and higher levels of total and direct bilirubin, ammonia, and lactate (for all, p<0.01). CONCLUSION: Infectious and indeterminate cases constituted the most common etiology of PALF, and the etiology was related to the prognosis in our series. Although high PELD and PRISM scores were related to poor prognoses, no sharp thresholds for individual laboratory tests could be elucidated. Liver transplantation was the only curative treatment for patients with poor prognoses and resulted in high survival rates (1-, 5-, and 10-year survival rates of 81.3%, 81.3%, and 75%, respectively) in our study.

Report of 3 Patients With Urea Cycle Defects Treated With Related Living-Donor Liver Transplant.

Urea cycle defects are a group of metabolic disorders caused by enzymatic disruption of the urea cycle pathway, transforming nitrogen to urea for excretion from the body. Severe cases present in early infancy with life-threatening metabolic decompensation, and these episodes of hyperammonemia can be fatal or result in permanent neurologic damage. Despite the progress in pharmacologic treatment, long-term survival is poor especially for severe cases. Liver transplant is an alternative treatment option, providing sufficient enzymatic activity and decreasing the risk of metabolic decompensation. Three patients with urea cycle defects received related living-donor liver transplants at our hospital. Patients presented with late-onset ornithine transcarbamylase deficiency, argininosuccinate lyase deficiency, and citrullinemia. Maximum pretransplant ammonia levels were between 232 and 400 µmol/L (normal range is 18-72 µmol/L), and maximum posttransplant values were 52 to 94 µmol/L. All patients stopped medical treatment and dietary protein restriction for urea cycle defects after transplant. The patient with late-onset ornithine transcarbamylase deficiency already had motor deficits related to recurrent hyperammonemia attacks pretransplant. A major improvement could not be achieved, and he is wheelchair dependent at the age of 6 years. The other 2 patients had normal motor and mental skills before transplant, which have continued 12 and 14 months after transplant. Hepatic artery thrombosis in the patient with the ornithine transcarbamylase deficiency, intraabdominal infection in the patient with argininosuccinate lyase deficiency, and posterior reversible encephalopathy syndrome in the patient with citrullinemia were early postoperative complications. Histopathologic changes in livers explanted from patients with ornithine transcarbamylase deficiency and citrullinemia were nonspecific. The argininosuccinate lyase-deficient patient had portoportal fibrosis and cirrhotic nodule formation. In conclusion, liver transplant was a lifesaving procedure for our patients. Proper timing for transplant is important because high ammonia levels may result in permanent neurologic damage; however, transplant at younger ages also may increase morbidity.

Acute liver failure in children: 20-year experience.

BACKGROUND/AIMS: We aimed to determine the causes, demographic findings, clinical status, outcomes, and prognostic risk factors of patients with acute liver failure admitted to Hacettepe University Children's Hospital between October 1987-October 2006. METHODS: This retrospective case study included 74 patients with acute liver failure according to the Pediatric Acute Liver Failure Study Group definition. RESULTS: The etiology of acute liver failure was metabolic in 26 (35.1%) and infectious in 21 (28.4%) patients. Sixteen (21.6%) patients had indeterminate causes. Wilson's disease (16/26 patients, 61.5%) was the most frequent metabolic disease, while hepatitis A (14/21 patients, 66.7%) was the most frequent infectious agent. Neurologic functions were normal in 21 (28.4%) patients. Forty-nine (66.2%) patients died and 24 (32.4%) recovered. Two patients underwent liver transplantation. The mortality rate was 82.9% for patients who were not transplanted but fulfilled King's College Hospital criteria and 45.4% for patients who were not suitable for transplantation. This difference was statistically significant (p=0.001). Total bilirubin >5.35 mg/dl, international normalized ratio (INR) >3.66 and prothrombin time >23.5 seconds were shown to be the risk factors to predict death. CONCLUSIONS: Metabolic and infectious etiologies were responsible for most of the acute liver failure cases. Clinical encephalopathy may not be present in children.

Salmonella gastroenteritis in children (clinical characteristics and antibiotic susceptibility): comparison of the years 1995-2001 and 2002-2008.

We document herein the prevalence and serotype distribution among Salmonella enterica strains isolated from children treated for diarrhea over two seven-year periods spanning 14 years. Four hundred and eight (1.38%) S. enterica cases were isolated among 29,601 diarrheal admissions. Among the Salmonella isolates, 63.7% were serogroup D and 29.9% were serogroup B. Overall, 21.7% of cases were under one year of age, with 2.1% being younger than three months. Bloody diarrhea was found in 18.8% of the cases. The resistance rates were 25.8%, 18.2%, 7.0%, 4.7%, and 0.3%, to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, ceftriaxone, and ciprofloxacin, respectively. In conclusion, our study has revealed that the predominance of Salmonella serogroup D continues. The clinical features of our patients were mostly mild, with no deaths or severe complications. While resistance to antimicrobial agents changes constantly, it is important to keep these strains under surveillance in order to formulate policies for the rational use of antimicrobial agents.

Prevalence of celiac disease in healthy Turkish school children.

OBJECTIVES: Epidemiological studies of celiac disease (CD) in Turkey have been performed only within some regions of the country. The aim of this study was to determine the prevalence of CD in Turkish school children. METHODS: Between 2006 and 2008, serum samples were collected from 20,190 students (age range, 6-17 years) in 139 schools in 62 cities from different regions of Turkey. CD was screened using IgA antitissue transglutaminase (IgA-tTG) and total serum IgA. Subjects with selective IgA deficiency were further tested for IgG-tTG. Serum samples positive for IgA or IgG-tTG were further tested for IgA antiendomysial antibodies (IgA-EMAs) using an indirect immunofluorescence method. Small-intestinal biopsy was offered to all subjects with tTG antibody positivity. RESULTS: Of the 20,190 subjects, 489 were antibody positive (IgA-tTG only in 270, both IgA-tTG and IgA-EMA in 215, and IgG-tTG in 4). Selective IgA deficiency was detected in 108 patients, and 4 of them were positive for IgG-tTG. An intestinal biopsy was conducted in 215 subjects (IgA-tTG positive in 110, IgA-tTG and IgA-EMA positive in 104, and IgG-tTG positive in 1). The biopsy findings of 95 children were consistent with CD. Thus, the estimated biopsy-proven prevalence was 1:212 children. The positive predictive value (PPV) for IgA-tTG plus EMA was 75.9%. PPV was 44.3% when only IgA-tTG was used. CONCLUSIONS: We estimate that the prevalence of CD is at least 0.47% in healthy Turkish school children. Screening for IgA-tTG plus EMA provided better results for diagnosis when compared with testing for IgA-tTG alone.