Human JAK1 gain of function causes dysregulated myelopoeisis and severe allergic inflammation

Primary atopic disorders are a group of inborn errors of immunity that skew the immune system toward severe allergic disease. Defining the biology underlying these extreme monogenic phenotypes reveals shared mechanisms underlying common polygenic allergic disease and identifies potential drug targets. Germline gain-of-function (GOF) variants in JAK1 are a cause of severe atopy and eosinophilia. Modeling the JAK1GOF (p.A634D) variant in both zebrafish and human induced pluripotent stem cells (iPSCs) revealed enhanced myelopoiesis. RNA-Seq of JAK1GOF human whole blood, iPSCs, and transgenic zebrafish revealed a shared core set of dysregulated genes involved in IL-4, IL-13, and IFN signaling. Immunophenotypic and transcriptomic analysis of patients carrying a JAK1GOF variant revealed marked Th cell skewing. Moreover, long-term ruxolitinib treatment of 2 children carrying the JAK1GOF (p.A634D) variant remarkably improved their growth, eosinophilia, and clinical features of allergic inflammation. This work highlights the role of JAK1 signaling in atopic immune dysregulation and the clinical impact of JAK1/2 inhibition in treating eosinophilic and allergic disease.

Biliary Atresia in 2021: Epidemiology, Screening and Public Policy

Biliary atresia (BA) is a rare newborn liver disease with significant morbidity and mortality, especially if not recognized and treated early in life. It is the most common cause of liver-related death in children and the leading indication for liver transplantation in the pediatric population. Timely intervention with a Kasai portoenterostomy (KPE) can significantly improve prognosis. Delayed disease recognition, late patient referral, and untimely surgery remains a worldwide problem. This article will focus on biliary atresia from a global public health perspective, including disease epidemiology, current national screening programs, and their impact on outcome, as well as new and novel BA screening initiatives. Policy challenges for the implementation of BA screening programs will also be discussed, highlighting examples from the North American, European, and Asian experience.

Cholangitis Definition and Treatment after Kasai Hepatoportoenterostomy for Biliary Atresia: A Delphi Process and International Expert Panel

(1) Background: Acute cholangitis during the first year after Kasai hepatoportoenterostomy (HPE) has a negative impact on patient and native liver survival. There are no consistent guidelines for the definition, treatment, and prophylaxis of cholangitis after HPE. The aim of this study was to develop definition, treatment, and prophylaxis guidelines to allow for expeditious management and for standardization in reporting. (2) Methods: the Delphi method, an extensive literature review, iterative rounds of surveys, and expert panel discussions were used to establish definition, treatment, and prophylaxis guidelines for cholangitis in the first year after HPE. (3) Results: Eight elements (pooled into two groups: clinical and laboratory/imaging) were identified to define cholangitis after HPE. The final proposed definitions for suspected and confirmed cholangitis are a combination of one element, respectively, two elements from each group; furthermore, the finding of a positive blood culture was added to the definition of confirmed cholangitis. The durations for prophylaxis and treatment of suspected and confirmed cholangitis were uniformly agreed upon by the experts. (4) Conclusions: for the first time, an international consensus was found for guidelines for definition, treatment, and prophylaxis for cholangitis during the first year after Kasai HPE. Applicability will need further prospective multicentered studies.

The effects of child anxiety and depression on concordance between parent-proxy and self-reported health-related quality of life for pediatric liver transplant patients

BACKGROUND

HRQOL is a key outcome following pediatric LT. Parent-proxy reports may substitute for patients unable to report their own HRQOL. This study compared parent-proxy and self-reported HRQOL in children who have undergone LT.

METHODS

Pediatric LT recipients between the ages of 8 and 18 years, and a parent, completed self and proxy versions of the PeLTQL questionnaire, PedsQL Generic and Transplant modules, and standardized measures of depression and anxiety.

RESULTS

Data from 129 parent-patient dyads were included. Median parent age was 44 years, and most (89%) were mothers. Median patient age was 2.5 years at LT and 13.6 years at the time of study participation. Parents had significantly lower scores than patients on PedsQL total generic (70.8 ± 18.5 and 74.3 ± 19.0, p = .01), PeLTQL coping and adjustment (63.0 ± 15.6 and 67.3 ± 16.2, p < .01), and social-emotional (66.3 ± 14.9 and 71.9 ± 15.6, p < .001) domains. Higher patient anxiety and depression were related to larger absolute differences between parent-proxy and self-reported scores on all HRQOL measures (all p < .05). In this disparity, parents reported higher HRQOL scores than their child as self-reported anxiety and depression scores increased.

CONCLUSIONS

Differences in concordance between parent-proxy and self-reported HRQOL scores can be more prominent when children have more symptoms of anxiety and depression. Children's mental health symptoms should be queried, if feasible, when interpreting differences in parent and child reports of HRQOL.

Sequential paternal haploidentical donor liver and HSCT in EPP allow discontinuation of immunosuppression post-organ transplant

BACKGROUND

EPP is characterized by photosensitivity and by liver disease. When LT is performed in EPP, recurrence often occurs in the allograft due to ongoing protoporphyrin production in bone marrow. Therefore, curative treatment requires allogeneic HSCT after LT. Long-term immunosuppression could be spared by using the same donor for both transplants.

METHODS

A 2-year-old girl with EPP in liver failure underwent liver transplant from her father. Transfusion and apheresis therapy were used to lower protoporphyrin levels before and after liver transplant. Ten weeks after liver transplant, she underwent HSCT, using the same donor. Conditioning was with treosulfan, fludarabine, cyclophosphamide, and ATG. GVHD prophylaxis was with abatacept, methotrexate, MMF, and tacrolimus. We followed the patient's erythrocyte protoporphyrin and liver and skin health for 2 years after transplant.

RESULTS

After hematopoietic stem cell engraftment, a decline in protoporphyrin levels was observed, with clinical resolution of photosensitivity. Liver biopsies showed no evidence of EPP. Mild ACR occurred and responded to steroid pulse. Two years post-HSCT, the patient has been weaned off all immunosuppression and remains GVHD and liver rejection free.

CONCLUSIONS

Sequential liver and HSCT from the same haploidentical donor are feasible in EPP. This strategy can allow for discontinuation of immune suppression.

Post-traumatic stress as a determinant of quality of life in pediatric solid-organ transplant recipients

Living with end-stage organ failure is associated with an accumulation of traumatic medical events, and despite recovery after solid-organ transplantation (SOT), many children continue to exhibit lower quality of life (QOL). Few studies have examined the relationship between post-traumatic stress disorder (PTSD) and QOL among pediatric SOT recipients. We conducted a retrospective, cross-sectional review of 61 pediatric SOT recipients (12 heart, 30 kidney, and 19 liver) to evaluate the association of PTSD with self-reported QOL. PTSD was measured by the Child Trauma Screening Questionnaire (CTSQ), and QOL was measured using the PedsQL and PedsQL Transplant Module (PedsQL-TM) surveys. Demographics, baseline, and contemporaneous factors were tested for independent association. SOT recipients were 15.2 (12.1-17.6) years old at survey completion. Median CTSQ score was 2 (1-3), highest in kidney recipients, and 13% were identified as high risk for PTSD. Median PedsQL score was 83 (70-91) and significantly associated with the CTSQ score (r = -.68, p < .001). Median PedsQL Transplant Module score was 89 (83-95) and similarly associated with the CTSQ score (r = -.64, p < .001). Age at time of surveys and presence of any disability were also independently associated with PedsQL and PedsQL-TM, respectively. When adjusted for Emotional Functioning, CTSQ remained associated with PedsQL subscores (r = -.65, p < .001). Trauma symptoms are a major modifiable risk factor for lower self-perceived QOL and represent a potentially important target for post-transplant rehabilitation. Additional research is needed to understand the root contributors to PTSD and potential treatments in this population.

Role of transient elastography and APRI in the assessment of pediatric cystic fibrosis liver disease

Background: Diagnosis and monitoring of cystic fibrosis liver disease (CFLD) is challenging. Transient elastography (TE) is a rapid, non-invasive method for assessing liver fibrosis. Its role in detecting fibrosis in CFLD has only begun to be explored. The aspartate aminotransferase to platelet ratio index (APRI) has been validated as a predictor of hepatic fibrosis in other chronic liver diseases. The purpose of this study was to assess the utility of APRI and TE in identifying liver fibrosis in pediatric CF patients. Methods: Patients aged 2–18 years were recruited from the British Columbia Children’s Hospital CF clinic. Patients were determined to have CFLD using standard criteria. Charts were reviewed, and each patient underwent TE. Results: Of the 55 patients included in the study (50.9% male, mean age 11.6 y), 22 (40%) had CFLD. All mean liver enzymes were higher in the CFLD group, notably alanine transaminase ( p = 0.031). Mean liver stiffness (LS) and APRI were also higher in the CFLD group (LS: 5.9 versus 4.5 kPa, p = 0.015; APRI: 0.40 versus 0.32, p = 0.119). Linear regression showed a mild positive association between the two ( r2 = 0.386). Conclusions: TE values were higher among CFLD patients and correlated with APRI values, suggesting that these tools may have clinical applications for identifying and following this population. Further research is needed on a larger scale to determine the relative value and clinical utility of TE and APRI among patients with CFLD.

Idiopathic splenomegaly in childhood and the spectrum of RAS-associated lymphoproliferative disease: a case report

Background

KRAS (KRAS proto-oncogene, GTPase; OMIM: 190,070) encodes one of three small guanosine triphosphatase proteins belonging to the RAS family. This group of proteins is responsible for cell proliferation, differentiation and inhibition of apoptosis. Gain-of-function variants in KRAS are commonly found in human cancers. Non-malignant somatic KRAS variants underlie a subset of RAS-associated autoimmune leukoproliferative disorders (RALD). RALD is characterized by splenomegaly, persistent monocytosis, hypergammaglobulinemia and cytopenia, but can also include autoimmune features and lymphadenopathy. In this report, we describe a non-malignant somatic variant in KRAS with prominent clinical features of massive splenomegaly, thrombocytopenia and lymphopenia.

Case presentation

A now-11-year-old girl presented in early childhood with easy bruising and bleeding, but had an otherwise unremarkable medical history. After consulting for the first time at 5 years of age, she was discovered to have massive splenomegaly. Clinical follow-up revealed thrombocytopenia, lymphopenia and increased polyclonal immunoglobulins and C-reactive protein. The patient had an unremarkable bone marrow biopsy, flow cytometry showed no indication of expanded double negative T-cells, while malignancy and storage disorders were also excluded. When the patient was 8 years old, whole exome sequencing performed on DNA derived from whole blood revealed a heterozygous gain-of-function variant in KRAS (NM_004985.5:c.37G > T; (p.G13C)). The variant was absent from DNA derived from a buccal swab and was thus determined to be somatic.

Conclusions

This case of idiopathic splenomegaly in childhood due to a somatic variant in KRAS expands our understanding of the clinical spectrum of RAS-associated autoimmune leukoproliferative disorder and emphasizes the value of securing a molecular diagnosis in children with unusual early-onset presentations with a suspected monogenic origin.

Fontan-Associated Liver Disease: Spectrum of Disease in Children and Adolescents

Background Information is evolving on liver disease in pediatric patients with Fontan physiology. The purpose of this investigation is to evaluate the spectrum of liver disease in a pediatric population of patients with Fontan physiology and evaluate transient elastography (TE) as a noninvasive marker of liver disease. Methods and Results We prospectively enrolled all children with Fontan physiology. All patients underwent comprehensive liver evaluation including liver enzymes (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase), aspartate transaminase to platelet ratio index, albumin, bilirubin, international normalized ratio, complete blood cell count, abdominal ultrasound, and TE. Transjugular liver biopsies and hemodynamic measurements were performed in a subset of patients. A total of 76 children (median, 11.7; interquartile range, 8.4-14.8 [56% male]) were evaluated, with 17 having a transjugular liver biopsy (median 14.8 years; interquartile range, 14.3-17.4). All biopsies showed pathological changes. The severity of liver pathology did not correlate with TE. There was a positive correlation between TE and time since Fontan (R=0.42, P<0.01), aspartate transaminase to platelet ratio index (R=0.29, P=0.02), aspartate transaminase (R=-0.42, P<0.01), and platelets (R=-0.42, P<0.01). Splenomegaly on abdominal ultrasound was correlated with TE (z=-2.2, P=0.03), low platelet count (z=1.9, P=0.05), low aspartate transaminase (z=1.9, P=0.02), and low alkaline phosphatase (z=2.4, P=0.02). Conclusions Liver disease was ubiquitous in our cohort of pediatric patients with Fontan Physiology. Given the correlation between TE and time from Fontan, TE shows potential as a prospective marker of liver pathology. However, individual measurements with TE do not correlate with the severity of pathology. Given the prevalence of liver disease in this population, protective measures of liver health as well as routine liver health surveillance should be implemented with consideration for hepatology consultation and biopsy in the event of abnormal liver biochemical markers or imaging.

Stability of hepatitis B viral load during pregnancy and implications for antepartum prophylaxis: A prospective cohort study

BACKGROUND: We examined changes in hepatitis B virus (HBV) viral loads (VLs) in pregnancy, their association with hepatitis B e antigen (HBeAg), and the associated infant outcomes. METHODS: We prospectively followed 132 mothers positive for hepatitis B surface antigen (HBsAg) and their 135 infants from 2011 to 2015 in Vancouver, British Columbia. Outcome measures included association between maternal HBeAg and high (>200,000 IU/mL) or low (≤200,000 IU/mL) HBV VL, changes in HBV VL through pregnancy, infant HBsAg status, and infant completion of the HBV vaccination series. RESULTS: Of the 91 participants with an available HBV VL, 13 (14.3%) had an HBV VL of more than 200,000 IU/mL. Of 59 participants with paired HBeAg and HBV VL in pregnancy, 6 had an HBV VL of more than 200,000 IU/mL; of interest, 2 of the 6 (33.3%) were HBeAg-negative. Thirty-eight participants had HBV VL results at both mid-trimester and delivery. For these 38 participants, Wilcoxon signed-ranks test for paired data found that an HBV VL remained stable ( p = .58). We observed no perinatal transmissions. However, 20.7% of infants did not have a documented complete HBV vaccination series, 20.0% did not have post-vaccination HBsAg testing completed, and 18% did not have anti-HBs titres measured by age 12 months. CONCLUSIONS: Our study demonstrates that HBeAg and HBV VL are not reliably predictive of each other. This supports the improved predictive value of VL measurement in pregnancy to risk stratify pregnant patients to offer antiviral treatment when indicated and further minimize the risk of perinatal transmission.

Universal screening of newborns for biliary atresia: Cost-effectiveness of alternative strategies

Objective

Biliary atresia, a rare newborn liver disease, is the most common cause of liver-related death in children and the main indication for paediatric liver transplantation. Early detection and surgical intervention with a Kasai portoenterostomy offers the best chance for long-term patient survival. We conducted a cost-effectiveness analysis to compare no universal screening with screening using either a home-based infant stool colour card with passive card distribution strategy, or conjugated bilirubin testing.

Methods

A Markov model was developed, with structure, costs, and probabilities informed by the literature and clinical expert opinion, to simulate a newborn cohort over a 10-year time horizon. Health benefits were expressed as life-years gained. This analysis was conducted from the perspective of the Canadian publicly funded health care system (all costs in Canadian dollars). Both deterministic and probabilistic analyses were conducted.

Results

Screening using a home-based colour card with passive card distribution was a cost-effective option. For a population of 392,902 annual births in Canada, this strategy cost approximately $192,000 more than no universal screening but led to eight life-years gained (incremental cost-effectiveness ratio (ICER) = $24,065 per life-year gained). Screening using conjugated bilirubin testing versus the colour card cost $2,369,199 more and led to five more life-years gained (ICER= $473,840 per life year gained), and so was not cost-effective.

Conclusions

A home-based screening program using infant stool colour cards with a passive distribution strategy could be highly cost-effective when administered at a low unit cost and with a reasonable screening performance.

Clinical Characteristics and Complications of Pediatric Liver Biopsy: A Single Centre Experience

INTRODUCTION

Percutaneous liver biopsy (LB) is the gold standard method for evaluation and management of patients with liver disease. The purpose of this study was to characterize pediatric patients undergoing LB at British Columbia Children's Hospital, and to determine the rate and timing of complications following the procedure.

MATERIAL AND METHODS

The medical records of all pediatric patients who underwent LB during a six-year retrospective study were reviewed to collect demographic and procedure-related data.

RESULTS

223 LBs were performed, and 179 of these biopsies were percutaneous or transjugular. Elevated liver enzymes and cholestasis together accounted for almost 70% of the indications for LB, and the histological analysis of liver tissue yielded a specific diagnosis in 89 % of the cases. There were no deaths and no major complications related to LB. The most frequent minor complication was pain (59% of LBs) and the other complications were bleeding-related and classified as minor. The vast majority of complications (88%) were recognized within 8 h of the LB.

CONCLUSIONS

LB is a valuable and safe procedure in pediatric patients with a low rate of complications. Pediatric patients can be discharged home safely should no complications occur within the first 8-12 h after the procedure.

A national retrospective study of paediatric end-stage liver disease as a predictor of change to second-line therapy in children with autoimmune hepatitis

BACKGROUND & AIMS

Adult studies of autoimmune hepatitis (AIH) have shown that the model of end-stage liver disease is associated with resistance to first-line treatment. Using a multicentre retrospective database, we sought to determine if the paediatric end-stage liver disease (PELD) score would similarly predict treatment resistance in paediatric AIH.

METHODS

One hundred and seventy-one children from 13 Canadian centres who fulfilled the International Autoimmune Hepatitis Group (IAIHG) criteria were included and assessed for change to second-line therapy within 24 months of primary treatment onset. Those with PSC overlap at presentation, or missing data on the PELD variables were excluded. PELD was calculated for all remaining patients. Univariate analysis and receiver-operator characteristic (ROC) curves were performed to determine the predictive ability of the PELD score to change to second-line therapy.

RESULTS

A total of 103 children were included with median age of 11 years (range 2-17). Mean PELD was -2.51±8.58. Second-line therapy was used within 24 months of diagnosis in 13 patients. Univariate analysis revealed that change to second-line therapy was associated with higher PELD (P=.028) and internal normalized ratio (INR) (P=.011). ROC curves for PELD and its individual components were performed. The strength of association was strongest with INR (AUC 0.72; CI: 0.58-0.86) although the composite PELD score also showed some predictive ability (AUC 0.67; CI: 0.52-0.81).

CONCLUSION

In this paediatric AIH cohort, higher PELD at presentation predicted change to second-line therapy within the first 2 years of follow-up. INR appeared to be the main contributor to that association.

Variability of diagnostic approach, surgical technique, and medical management for children with biliary atresia in Canada - Is it time for standardization?

BACKGROUND

The Canadian 4-year native liver survival rate for biliary atresia (BA) after Kasai Portoenterostomy (KP) is 39%. The Canadian Biliary Atresia Registry (CBAR) was used to examine variability of surgical and medical management of BA.

METHODS

Gastroenterologists and surgeons in all 14 Canadian pediatric tertiary centers were invited to complete an online survey of their BA management practices.

RESULTS

Of gastroenterologists, diagnostic procedures included liver biopsy (92%), HIDA scan (58%), and percutaneous cholangiogram (46%). Surgeons reported Roux-en-Y lengths of 20-50cm with 78% avoiding diathermy at the portal plate; 16% performed laparoscopic exploration, but none laparoscopic KP. Postoperative corticosteroids and antibiotics were used by 24% and 85% of gastroenterologists, respectively, with similar rates for surgeons. At discharge, gastroenterologists prescribed oral antibiotics (80%), and ursodeoxycholic acid (95%), while surgeons reported lower rates (62% and 55%). Considerable variation existed in follow-up monitoring. No center had a standard protocol for evaluating suspected cholangitis. There was a lack of consensus for defining failed KP and referral criteria for transplant evaluation.

CONCLUSION

In Canada, treatment of BA is not centralized, and there is variability in diagnostic approaches and management. Collaboration through CBAR will allow for implementation and evaluation of standardized surgical and medical management with a goal to improve outcomes.

LEVEL OF EVIDENCE

Survey study. Level IV evidence.

Biliary atresia and other cholestatic childhood diseases: Advances and future challenges

Biliary Atresia and other cholestatic childhood diseases are rare conditions affecting the function and/or anatomy along the canalicular-bile duct continuum, characterised by onset of persistent cholestatic jaundice during the neonatal period. Biliary atresia (BA) is the most common among these, but still has an incidence of only 1 in 10-19,000 in Europe and North America. Other diseases such as the genetic conditions, Alagille syndrome (ALGS) and Progressive Familial Intrahepatic Cholestasis (PFIC), are less common. Choledochal malformations are amenable to surgical correction and require a high index of suspicion. The low incidence of such diseases hinder patient-based studies that include large cohorts, while the limited numbers of animal models of disease that recapitulate the spectrum of disease phenotypes hinders both basic research and the development of new treatments. Despite their individual rarity, collectively BA and other cholestatic childhood diseases are the commonest indications for liver transplantation during childhood. Here, we review the recent advances in basic research and clinical progress in these diseases, as well as the research needs. For the various diseases, we formulate current key questions and controversies and identify top priorities to guide future research.

The Canadian Biliary Atresia Registry: Improving the care of Canadian infants with biliary atresia

Biliary atresia is the most common cause of end-stage liver disease and liver cirrhosis in children, and the leading indication for liver transplantation in the paediatric population. There is no cure for biliary atresia; however, timely diagnosis and early infant age at surgical intervention using the Kasai portoenterostomy optimize the prognosis. Late referral is a significant problem in Canada and elsewhere. There is also a lack of standardized care practices among treating centres in this country. Biliary atresia registries currently exist across Europe, Asia and the United States. They have provided important evidence-based information to initiate changes to biliary atresia care in their countries with improvements in outcome. The Canadian Biliary Atresia Registry was initiated in 2013 for the purpose of identifying best standards of care, enhancing public education, facilitating knowledge translation and advocating for novel national public health policy programs to improve the outcomes of Canadian infants with biliary atresia.

Incidence and Characteristics of Autoimmune Hepatitis

BACKGROUND AND OBJECTIVES

Autoimmune hepatitis (AIH) is a progressive inflammatory liver disease of unknown etiology, with limited population-based estimates of pediatric incidence. We reported the incidence of pediatric AIH in Canada and described its clinical characteristics.

METHODS

We conducted a retrospective cohort study of patients aged <18 years diagnosed with AIH between 2000-2009 at all pediatric centers in Canada.

RESULTS

A total of 159 children with AIH (60.3% female, 13.2% type 2 AIH) were identified. Annual incidence was 0.23 per 100000 children. Median age at presentation for type 1 was 12 years (interquartile range: 11-14) versus 10 years for type 2 (interquartile range: 4.5-13) (P = .03). Fatigue (58%), jaundice (54%), and abdominal pain (49%) were the most common presenting symptoms. Serum albumin (33 vs 38 g/L; P = .03) and platelet count (187 000 vs 249 000; P <.001) were significantly lower and the international normalized ratio (1.4 vs 1.2; P <.001) was higher in cirrhotic versus noncirrhotic patients. Initial treatment included corticosteroids (80%), azathioprine (32%), and/or cyclosporine (13%). Response to treatment at 1 year was complete in 90%, and partial in 3%. 3% of patients had no response, and 3% responded and later relapsed. Nine patients underwent liver transplantation, and 4 patients died at a mean follow-up of 4 years.

CONCLUSIONS

AIH is uncommon in children and adolescents in Canada. Type 1 AIH was diagnosed 5.5 times more frequently than type 2 AIH. Most patients respond well to conventional therapy, diminishing the need for liver transplantation.

Home-based screening for biliary atresia using infant stool colour cards: a large-scale prospective cohort study and cost-effectiveness analysis

OBJECTIVE

Biliary atresia (BA), a leading cause of paediatric liver failure and liver transplantation, manifests by three weeks of life as jaundice with acholic stools. Poor outcomes due to delayed diagnosis remain a problem worldwide. We evaluated and assessed the cost-effectiveness of methods of introducing a BA Infant Stool Colour Card (ISCC) screening programme in Canada.

SETTING AND METHODS

A prospective study at BC Women's Hospital recruited consecutive healthy newborns through six incrementally more intensive screening approaches. Under the baseline "passive" strategy, families received ISCCs at maternity, with instructions to monitor infant stool colour daily and return the ISCC by mail at age 30 days. Additional strategies were: ISCC mailed to family physician; reminder letters or telephone calls to families or physicians. Random telephone surveys of ISCC non-returners assessed total card utilization. Primary outcome was ISCC utilization rate expressed as a composite outcome of the ISCC return rate and non-returned ISCC use. Markov modelling was used to predict incremental costs and life years gained from screening (passive and reminder), compared with no screening, over a 10-year time horizon.

RESULTS

6,187 families were enrolled. Card utilization rates in the passive screening strategy were estimated at 60-94%. For a Canadian population, the increase in cost for passive screening, compared with no screening, is $213,584 and the gain in life years is 9.7 ($22,000 per life-year gained).

CONCLUSIONS

A BA ISCC screening programme targeting families of newborns is feasible in Canada. Passive distribution of ISCC at maternity is potentially effective and highly cost-effective.

CLMP is required for intestinal development, and loss-of-function mutations cause congenital short-bowel syndrome

BACKGROUND & AIMS

Short-bowel syndrome usually results from surgical resection of the small intestine for diseases such as intestinal atresias, volvulus, and necrotizing enterocolitis. Patients with congenital short-bowel syndrome (CSBS) are born with a substantial shortening of the small intestine, to a mean length of 50 cm, compared with a normal length at birth of 190-280 cm. They also are born with intestinal malrotation. Because CSBS occurs in many consanguineous families, it is considered to be an autosomal-recessive disorder. We aimed to identify and characterize the genetic factor causing CSBS.

METHODS

We performed homozygosity mapping using 610,000 K single-nucleotide polymorphism arrays to analyze the genomes of 5 patients with CSBS. After identifying a gene causing the disease, we determined its expression pattern in human embryos. We also overexpressed forms of the gene product that were and were not associated with CSBS in Chinese Hamster Ovary and T84 cells and generated a zebrafish model of the disease.

RESULTS

We identified loss-of-function mutations in Coxsackie- and adenovirus receptor-like membrane protein (CLMP) in CSBS patients. CLMP is a tight-junction-associated protein that is expressed in the intestine of human embryos throughout development. Mutations in CLMP prevented its normal localization to the cell membrane. Knock-down experiments in zebrafish resulted in general developmental defects, including shortening of the intestine and the absence of goblet cells. Because goblet cells are characteristic for the midintestine in zebrafish, which resembles the small intestine in human beings, the zebrafish model mimics CSBS.

CONCLUSIONS

Loss-of-function mutations in CLMP cause CSBS in human beings, likely by interfering with tight-junction formation, which disrupts intestinal development. Furthermore, we developed a zebrafish model of CSBS.

Biliary atresia with associated structural malformations in Canadian infants

BACKGROUND

Biliary atresia (BA) is associated with extrahepatic congenital malformations in a minority of affected infants. The term commonly applied to this subgroup is 'BASM' for biliary atresia splenic malformation syndrome, as spleen abnormalities are prominent.

AIMS AND METHODS

To examine clinical outcome in Canadian BA patients with extrahepatic congenital malformations in the Canada-wide BA database of patients born between 1985 and 2002, and additionally, to recharacterized the syndrome. Patients had ≥1 of the following: a/polysplenia, abnormal abdominal situs, intestinal malrotation, abdominal vascular anomaly or congenital heart disease.

RESULTS

Among 328 BA patients, 44 (13%) had associated congenital abnormalities. Intra-abdominal anomalies included polysplenia (n=25), abnormal abdominal situs (n=9), intestinal malrotation (n=19), portal vein anomaly (n=12), hepatic artery anomaly (n=3) and inferior vena cava interruption (n=20). Twenty-six patients had cardiac malformations including pulmonary stenosis (n=11), ventricular septal defect (n=10), atrial septal defect (n=7), total anomalous pulmonary venous return (n=3), double outlet right ventricle (n=3), tetralogy of Fallot (n=2), atrioventricular canal (n=2), dextrocardia (n=2), bicuspid aortic valve (n=2), hypoplastic left heart (n=1) and partial anomalous pulmonary venous return (n=1). Age at Kasai operation, performance of liver transplant, overall survival, post-Kasai native liver survival and transplant survival were comparable to isolated BA. Presence of polysplenia or complex cardiac disease did not reduce post-Kasai native liver survival. Three patients had ≥2 typical abnormalities without polysplenia: thus, splenic malformations are not essential to this BA subgroup. Hierarchical cluster analysis demonstrated characteristic abnormalities grouped in a multiplicity of combinations, consistent with a spectrum of defective lateralization.

CONCLUSION

We suggest that the acronym 'BASM' be redefined as 'biliary atresia structural malformation'.

Abnormal liver transaminases and conjugated hyperbilirubinemia at presentation of acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood. While hepatitis is a well-known complication during the treatment phase of ALL, the association of abnormal liver biochemistries at initial presentation of leukemia is poorly described. The aim of this study is to examine the prevalence and assess the clinical impact of hepatitis at diagnosis in children with ALL.

PROCEDURE

All children diagnosed with ALL at BC Children's Hospital between 2001 and 2006 were included. Charts were reviewed and data recorded to a computerized spreadsheet. Descriptive statistical analyses were performed.

RESULTS

One hundred forty-seven ALL patients were identified. Over one third of patients had abnormal liver transaminase values (AST and/or ALT). Of the patients with abnormal transaminases, (52%) had ALT elevations twice the upper limit of normal. Risk factors for elevated transaminases included a high WBC count at diagnosis, older age, bulky disease, and T-cell leukemia. Conjugated hyperbilirubinemia was observed in 3.4% of subjects. Of these cases, 60% received steroids prior to induction chemotherapy and all had rapid resolution of their hyperbilirubinemia to normal levels.

CONCLUSIONS

Elevated transaminases are common at initial presentation of ALL and are likely due to hepatic injury from leukemic infiltrates. Conjugated hyperbilirubinemia at presentation may require treatment modification and dose reduction. A short course of steroids prior to initiation of induction chemotherapy appears to result in rapid resolution of the hyperbilirubinemia with subsequent ability to provide full dosing of induction chemotherapy.

Biliary atresia: the Canadian experience

OBJECTIVE

To determine the outcomes of Canadian children with biliary atresia.

STUDY DESIGN

Health records of infants born in Canada between January 1, 1985 and December 31, 1995 (ERA I) and between January 1, 1996 and December 31, 2002 (ERA II) who were diagnosed with biliary atresia at a university center were reviewed.

RESULTS

349 patients were identified. Median patient age at time of the Kasai operation was 55 days. Median age at last follow-up was 70 months. The 4-year patient survival rate was 81% (ERA I = 74%; ERA II = 82%; P = not significant [NS]). Kaplan-Meier survival curves for patients undergoing the Kasai operation at age < or = 30, 31 to 90, and > 90 days showed 49%, 36%, and 23%, respectively, were alive with their native liver at 4 years (P < .0001). This difference continued through 10 years. The 2- and 4-year post-Kasai operation native liver survival rates were 47% and 35% for ERA I and 46% and 39% for ERA II (P = NS). A total of 210 patients (60%) underwent liver transplantation; the 4-year transplantation survival rate was 82% (ERA I = 83%, ERA II = 82%; P = NS).

CONCLUSIONS

This is the largest outcome series of North American children with biliary atresia at a time when liver transplantation was available. Results in each era were similar. Late referral remains problematic; policies to ensure timely diagnosis are required. Nevertheless, outcomes in Canada are comparable to those reported elsewhere.

Inflammatory bowel disease in the South Asian pediatric population of British Columbia

BACKGROUND

Geographical differences, population migration, and changing demographics suggest an environmental role in prevalence, modulation, and phenotypic expression of inflammatory bowel disease (IBD).

AIM

To determine the incidence of IBD and disease subtype in the pediatric South Asian population in British Columbia (BC) compared with non-South Asian IBD patients in the same geographic area.

METHODS

Chart review with data collected for all patients <or=16 yr of age diagnosed with IBD at B.C. Children's hospital, January 1985 to June 2005. Age, gender, family history, duration of symptoms, type, and extent of disease were extracted. Identified South Asian subjects were prospectively interviewed.

RESULTS

Seventy-five South Asian patients were diagnosed with IBD, 48% Crohn's disease (CD), 33.3% ulcerative colitis (UC), and 18.7% with indeterminate colitis (IC), in contrast to 71%, 18.8%, and 10.2%, respectively, in the non-South Asian population. The incidence rate for South Asian IBD patients, for the period 1996-2001 was 15.19/10(5) (6.41/10(5) for CD, 6.70/10(5) for UC, and 2.08/10(5) for IC) compared with 5.19/10(5) for the non-South Asian IBD group (3.69/10(5), 0.96/10(5), and 0.54/10(5), respectively). The South Asian male/female ratio was significantly different from that observed for the rest of the population.

CONCLUSION

These data suggest a significantly higher incidence of IBD in the South Asian pediatric population compared with the rest of the BC pediatric population, with a different pattern of phenotypic expression, a male predominance, and more extensive colonic disease. These data suggest a potential effect of migration, and environmental and lifestyle change on the incidence of IBD and disease subtype.

Diagnosing autoimmune hepatitis in children: is the International Autoimmune Hepatitis Group scoring system useful?

BACKGROUND & AIMS

In 1999, the International Autoimmune Hepatitis Group (IAIHG) modified a scoring system to differentiate adult patients with definite or probable autoimmune hepatitis (AIH) from those with other forms of chronic liver disease. We assessed the use of the scoring system in children.

METHODS

Twenty-eight pediatric patients with AIH and/or sclerosing cholangitis were reviewed. Clinical, laboratory, and histologic data were collected to score patients both before and after standard treatment.

RESULTS

There were 8 boys and 20 girls. The median age at diagnosis was 11 years (range, 2-16 years). Twenty-one of 28 children were diagnosed with AIH, 4 as isolated primary sclerosing cholangitis (PSC), and 3 as overlap syndrome. At presentation, 18 of 21 (86%) with AIH scored as definite AIH and 3 of 21 (14%) scored as probable. No patient clinically diagnosed as AIH scored as other. Seven of 28 patients had proven PSC. All patients with isolated PSC scored as other. The 3 with overlap syndrome scored as definite AIH. When the gamma-glutamyltranspeptidase (GGT) ratio was substituted for the alkaline phosphatase (ALP) ratio, 5 patients were reclassified from definite to probable AIH. Four of these 5 had an incomplete response to therapy, and 2 of 4 have confirmed overlap syndrome.

CONCLUSIONS

The IAIHG scoring system has a use in children. Patients who fall into the other category should have cholangiographic imaging. Using the GGT ratio instead of the ALP ratio in the IAIHG score may improve the specificity for children, identifying those likely to have biliary disease. When GGT is used, patients classified as needing probable pretreatment should be considered for biliary imaging.

Neonatal cholestasis: a red alert for the jaundiced newborn

Neonatal jaundice may indicate cholestasis rather than a benign, physiological condition. Any four-week-old newborn with persistent jaundice should have a fractionated bilirubin screen to determine whether the hyperbilirubinemia is unconjugated. Conjugated hyperbilirubinemia, a hallmark of neonatal cholestasis, is pathological and requires further investigation. These infants need prompt diagnosis, early intervention and careful follow-up to ensure continued growth and development. Recent progress in the physiology of bile flow is reviewed, and the evaluation and management of neonatal cholestasis are summarized. Further advances in delineating the cellular and molecular processes that regulate bile acid metabolism in both health and disease will lead to a greater understanding of the conditions causing neonatal cholestasis. Unravelling the etiopathogenesis of these neonatal cholestatic disorders will allow the development of novel diagnostic and therapeutic interventions that ultimately will effectuate the prognosis for these young patients.

Life-threatening gastrointestinal hemorrhage due to juvenile polyposis

A 14-yr-old, previously healthy boy presented with massive lower GI hemorrhage. After the routine endoscopic and radiological evaluation, laparotomy and intraoperative colonoscopy revealed multiple polyps in the colon. A hemicolectomy was performed because of the severity of hemorrhage. A diagnosis of juvenile polyposis was made based upon histological findings and the family history. This is an extremely unusual presentation of juvenile polyposis and has been reported only once before. The clinical features, diagnosis, and therapeutic options for juvenile polyposis are discussed. Juvenile polyposis, although a rare condition in the pediatric population, should be considered in the differential diagnosis of life-threatening GI hemorrhage.

Vascular abnormalities in Adams-Oliver syndrome: cause or effect?

We describe a young girl diagnosed with the Adams-Oliver syndrome (AOS) associated with double outlet right ventricle, portal hypertension, and pulmonary hypertension. We hypothesize that a congenital vascular abnormality is the underlying pathogenesis and that the cutaneous defects characteristically seen in AOS represent the most common manifestation of this. We suggest that AOS should not merely be considered a syndrome consisting of aplasia cutis congenita and terminal transverse limb defects but rather a constellation of clinical findings resulting from an early embryonic vascular abnormality.

Vascular abnormalities in Adams-Oliver syndrome: cause or effect?

We describe a young girl diagnosed with the Adams-Oliver syndrome (AOS) associated with double outlet right ventricle, portal hypertension, and pulmonary hypertension. We hypothesize that a congenital vascular abnormality is the underlying pathogenesis and that the cutaneous defects characteristically seen in AOS represent the most common manifestation of this. We suggest that AOS should not merely be considered a syndrome consisting of aplasia cutis congenita and terminal transverse limb defects but rather a constellation of clinical findings resulting from an early embryonic vascular abnormality.

Rejection of murine congenic bile ducts: a model for immune-mediated bile duct disease

Immune-mediated injury of prenatal and postnatal extrahepatic bile duct epithelium has been poorly characterized. In a transplantation model of bile duct allografts, segments of the common bile duct from fetal day 18, postnatal day 7 and day 21, and adult (greater than 6-weeks) mice were grafted under the renal capsule of adult congenic mice. The progression of rejection injury in these bile duct allografts was then followed by histological evaluation at 1-week intervals. After 3 weeks there was a significant difference in the number of fetal congenic bile duct grafts that had maintained their luminal architecture compared with the more mature adult congenic grafts that had fibrosclerosed. The onset and progression of the rejection injury in the adult congenic bile duct grafts was associated with an induction of class I and class II histocompatibility antigen expression in the adult bile duct epithelium; the severity of this injury could be attenuated by treatment of the recipient mice with cyclosporin A. Thus, the fibrosclerosing lesion of extrahepatic ducts observed in this model of rejection injury is similar to the histopathology of neonatal biliary atresia or primary sclerosing cholangitis, and susceptibility to this injury is dependent on the age of the donor tissue. The immune nature of the injury and the ontogeny of expression of histocompatibility antigen in bile duct tissue indicate that the above factors may be important to the pathogenesis of these extrahepatic bile duct diseases. This experimental model may be used to test for novel factors that may modulate immune responses directed against extrahepatic bile duct epithelium.

Food allergy: facts and fiction

Hypersensitivity reactions to dietary products are especially common in the pediatric population, yet food allergy as a distinct clinical entity remains poorly defined. The clinicopathologic features of this syndrome can vary considerably from patient to patient; no reliable diagnostic laboratory tests are available, and some of the treatment regimens are controversial. The pathogenesis of this condition is not well understood. An important factor is the role of the intestinal mucosal barrier in the regulation of uptake of dietary antigen from the intestinal tract. Recently, significant differences have been observed between the features of the immature newborn and the mature adult intestinal mucosal barriers. These findings may be of fundamental importance to the pathogenesis of food allergy and are currently an area of intense research.

Temporal changes in plasma levels and metabolism of ketone bodies by liver and brain after ethanol and/or starvation in C57BL/6J mice

The effects of ethanol and starvation on ketone body production and utilization were investigated. In the first experiment, adult C57BL/6J mice were divided into four groups: (i) control (fed); (ii) starvation (up to 31 h); (iii) ethanol (acute 5 g/kg i.p.); (iv) ethanol (ETOH) + starvation. Plasma ketone body (KB) concentrations in control mice remained constant at approx. 0.37 mM. The levels of KBs in starved mice began to increase at about 7 h and rose to a peak of 2.5 mM at about 24 h, then fell to 1.8 mM at 31 h. The levels in mice treated with ETOH began to rise soon after injection, reached 1.5 mM at 10 h, and returned to control levels by 15 h. Although there was no difference in elevated levels of KBs between two groups of mice treated with ETOH plus starvation and ETOH alone at 7-10 h, the level continued to rise steadily to 2.0 mM through 31 h in the former group. At 10 h post ETOH, mice either fed ad lib. or fasted had increased hepatic capacity to synthesize acetoacetate (AcAc) from palmitate; this effect was prolonged and enhanced by continued fasting for 24 h. In the brain, the rate of AcAc oxidation was twice that for beta-hydroxybutyrate (beta OHB) and glucose. Neither ETOH nor starvation affected energy production from KB and glucose. AcAc was also utilized for fatty acid synthesis and the rate of synthesis was stimulated by ETOH at 10 h after injection. The rate of lipogenesis from beta OHB accounted for less than 10% of that from AcAc. Together these experiments demonstrate that ETOH increases both hepatic ketone production and plasma KB levels for at least 10 h. ETOH alone led to elevated KB levels long before the rise due to starvation. In brain, at 10 h, an increased capacity to utilize AcAc for lipogenesis was found. The results indicate that ETOH through the production of KBs could provide an important source of energy and lipid precursors for the brain of mice.

Glucose protects DBA/2J mice from audiogenic seizures: correlation with brain glycogen levels

The time courses of changes in liver, blood, and brain cortical glucose and glycogen levels were measured in 21-day-old DBA/2J mice after an IP injection of 10 g/kg glucose. Other mice were injected with glucose and tested for susceptibility to audiogenic seizures (AGS). Susceptibility to AGS fell from maximal levels to complete protection by 4 h, remained low through 6 h, then began to return to control levels by 8 h. Liver, blood, and brain glucose levels all rose to a peak soon after the injection, then fell linearly and returned to control levels by 6-8 h. Changes in brain glycogen levels reflected changes in AGS susceptibility.

A proposed mechanism for the anticonvulsant action of valproate

Valproate (n-dipropylacetate), the most recent major anticonvulsant drug, is unique in that it is a short-chained branched fatty acid with no cyclic components. It is proposed that its anticonvulsant action may be due to its stimulation of the beta-oxidation pathway, with a concomitant whole-body system shift toward metabolic acidosis. The circulating ketone bodies may then be utilized by brain, allowing an increased brain energy reserve and a greater tolerance to a transient stimulation which would have, without Valproate, triggered an epileptic seizure.