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Background Precision in estimating placebo rates is important for clinical trial design. Aim To quantify placebo rates across relevant endpoints in Crohn’s disease [CD] trials and identify the factors influencing these rates in a contemporary meta-analysis. Methods We searched MEDLINE, EMBASE, and CENTRAL from inception to March 2021. Eligible studies were placebo-controlled trials of pharmacological interventions for CD. Placebo response and remission rates for induction and maintenance trials were extracted and pooled by random-effects to quantify placebo rates across studies. Mixed-effects meta-regression was used to evaluate the effects of study-level characteristics on placebo rates. Results In 125 studies [91 induction, 46 maintenance], placebo clinical remission and response rates for induction studies were 18% (95% confidence interval [CI] 16, 21%], and 32% [95% CI 29, 35%], respectively, and for maintenance studies were 28% [95% CI 23, 34%] and 30% [95% CI 24, 37%], respectively. Endoscopic remission and response rates in induction studies were 8% [95% CI 4, 18%] and 16% [95% CI 11, 23%], respectively. Trials enrolling patients with prior biologic exposure, longer disease duration, and higher CD activity index scores were associated with lower placebo clinical remission rates. Increased duration of follow-up, more follow-up visits, and a greater proportion of patients with colonic disease distribution were associated with higher clinical placebo rates. Conclusions Placebo remission and response rates in CD trials vary according to the phase of the trial, endpoint assessed, and induction or maintenance design. These contemporary estimates will help to inform future CD trial design.

BACKGROUND The phase 3 (UNIFI) trial of ustekinumab (anti-interleukin 12/23) demonstrated efficacy even after prior biologic failure in adult ulcerative colitis (UC), but paediatric data are lacking. AIM To prospectively monitor efficacy and serum concentrations of ustekinumab given to children with UC refractory to other biologics. METHODS Children with anti-TNF refractory UC initiating ustekinumab intravenously at sites of the Canadian Children IBD Network prior to 12/2019 are included. The primary endpoint was steroid-free clinical remission with subcutaneous ustekinumab at 52 weeks (Paediatric Ulcerative Colitis Activity Index

Background Targeting histological remission or response in Crohn's disease (CD) is not recommended in clinical practice guidelines or as an outcome in clinical trials due to uncertainties regarding index validity and prognostic relevance. Aims To conduct a modified RAND/University of California Los Angeles appropriateness process with the goal of producing a framework to standardise histological assessment of CD activity in clinical trials. Methods A total of 115 statements generated from literature review and expert opinion were rated on a scale of 1-9 by a panel of 11 histopathologists and 6 gastroenterologists. Statements were classified as inappropriate, uncertain or appropriate based upon the median panel rating and degree of disagreement. Results The panellists considered it important to measure histological activity in clinical trials to determine efficacy and that absence of neutrophilic inflammation is an appropriate histological target. They were uncertain whether the Global Histological Activity Score was an appropriate instrument for measuring histological activity. The Geboes Score and Robarts Histopathology Index were considered appropriate. Two biopsies from five segments should be biopsied, and the colon and the ileum should be analysed separately for all indices. Endoscopic mucosal appearance should guide biopsy procurement site with biopsies taken from the ulcer edge, or the most macroscopically inflamed area in the absence of ulcers. Conclusion We evaluated the appropriateness of items for assessing histological disease activity in CD clinical trials. These items will be used to develop a novel histological index.

Proactive therapeutic drug monitoring (TDM) has been proposed to improve outcomes in patients with inflammatory bowel disease (IBD) treated with tumor necrosis factor (TNF)α antagonists. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing proactive TDM with conventional management in patients with IBD.We identified RCTs in patients with IBD treated with TNFα antagonists comparing proactive TDM (routine assessments of trough concentration with dose adjustments to maintain predetermined trough concentration, regardless of disease activity) with conventional management (clinically driven dose adjustments). The primary outcome was failure to maintain clinical remission. Certainty of evidence was appraised using Grading of Recommendations, Assessment, Development and Evaluations.On meta-analysis of 9 RCTs (8 RCTs in adults, and focusing on maintenance phase), there was no significant difference in the risk of failing to maintain clinical remission in patients who underwent proactive TDM (267/709; 38%) vs conventional management (292/696; 42%) (relative risk [RR], 0.96; 95% confidence interval [CI], 0.81-1.13) with moderate heterogeneity (inconsistency index = 36%) (Grading of Recommendations, Assessment, Development and Evaluations; low certainty evidence), with no differences in patients with Crohn's disease (RR, 0.87 ; 95% CI, 0.66-1.15) and ulcerative colitis (RR, 0.88; 95% CI, 0.72-1.07). Disease duration, concomitant immunomodulators, disease activity at baseline, and optimization of therapy before randomization did not modify this association. No differences were observed in risk of developing antidrug antibodies or serious adverse events. Patients in the proactive TDM arm were more likely to undergo dose escalation (RR, 1.56; 95% CI, 1.25-1.94).Routine proactive TDM to target biologic concentration to specific thresholds, regardless of disease activity, did not offer clinical benefit in patients with IBD treated with TNFα antagonists in RCTs conducted to date. We cannot exclude the possibility of benefit in disease subtypes and phases of therapy (induction) not represented in these RCT populations.

Background Data on the association between early postinduction serum adalimumab (ADA) trough levels (TLs) and objective outcomes are scarce. The aim of this study was to investigate whether early ADA TLs at weeks 4 and 8 are associated with clinical and biomarker remission at week 24 in pediatric Crohn’s disease (CD). Methods Adalimumab TLs at weeks 4 and 8 were prospectively measured in anti-TNF-naïve children initiating treatment with ADA monotherapy for luminal inflammatory CD. The primary outcome was combined clinical and biomarker remission at week 24, defined as achieving steroid-free clinical remission (Pediatric CD activity index Results Among 65 patients, 39 (60%) achieved combined clinical/biomarker remission at week 24 without dose escalation. Adalimumab TLs at both weeks 4 and 8 were significantly higher in remitters vs nonremitters at week 24 (P Conclusion Greater early ADA exposure is associated with superior clinical/biomarker outcomes at week 24.

Background & Aims: A proportion of infants and young children with inflammatory bowel diseases (IBDs) have subtypes associated with a single gene variant (monogenic IBD). We aimed to determine the prevalence of monogenic disease in a cohort of pediatric patients with IBD. Methods: We performed whole-exome sequencing analyses of blood samples from an unselected cohort of 1005 children with IBD, aged 0–18 years (median age at diagnosis, 11.96 years) at a single center in Canada and their family members (2305 samples total). Variants believed to cause IBD were validated using Sanger sequencing. Biopsies from patients were analyzed by immunofluorescence and histochemical analyses. Results: We identified 40 rare variants associated with 21 monogenic genes among 31 of the 1005 children with IBD (including 5 variants in XIAP, 3 in DOCK8, and 2 each in FOXP3, GUCY2C, and LRBA). These variants occurred in 7.8% of children younger than 6 years and 2.3% of children aged 6–18 years. Of the 17 patients with monogenic Crohn’s disease, 35% had abdominal pain, 24% had nonbloody loose stool, 18% had vomiting, 18% had weight loss, and 5% had intermittent bloody loose stool. The 14 patients with monogenic ulcerative colitis or IBD-unclassified received their diagnosis at a younger age, and their most predominant feature was bloody loose stool (78%). Features associated with monogenic IBD, compared to cases of IBD not associated with a single variant, were age of onset younger than 2 years (odds ratio [OR], 6.30; P = .020), family history of autoimmune disease (OR, 5.12; P = .002), extra-intestinal manifestations (OR, 15.36; P < .0001), and surgery (OR, 3.42; P = .042). Seventeen patients had variants in genes that could be corrected with allogeneic hematopoietic stem cell transplantation. Conclusions: In whole-exome sequencing analyses of more than 1000 children with IBD at a single center, we found that 3% had rare variants in genes previously associated with pediatric IBD. These were associated with different IBD phenotypes, and 1% of the patients had variants that could be potentially corrected with allogeneic hematopoietic stem cell transplantation. Monogenic IBD is rare, but should be considered in analysis of all patients with pediatric onset of IBD.

Background The effectiveness and value of teledermatology and face-to-face workflows for diagnosing lesions are not adequately understood. Objective We compared the risks of biopsy and cancer diagnosis among 2 face-to-face workflows (direct referral and roving dermatologist) and 4 teledermatology workflows. Methods Retrospective study of 59,279 primary care patients presenting with a lesion from January through June 2017. Results One teledermatology workflow achieved high-resolution images with use of a dermatoscope-fitted digital camera, a picture archiving and communication system, and image retrieval to a large computer monitor (in contrast to a smartphone screen). Compared with direct referral, this workflow was associated with a 9% greater probability of cancer detection (95% confidence interval [CI], 2%-16%), a 4% lower probability of biopsy (relative risk, 0.96; 95% CI, 0.93-0.99), and 39% fewer face-to-face visits (relative risk, 0.61; 95% CI, 0.57-0.65). Other workflows were less effective. Limitations Differing proficiencies across teledermatology workflows and selection of patients for direct referral could have caused bias. Conclusion Implementation is critical to the effectiveness of teledermatology.

Inflammatory bowel disease (IBD), clinically defined as Crohn’s disease (CD), ulcerative colitis (UC), or IBD-unclassified, results in chronic inflammation of the gastrointestinal tract in genetically susceptible hosts. Pediatric onset IBD represents ≥ 25% of all IBD diagnoses and often presents with intestinal stricturing, perianal disease, and failed response to conventional treatments. NOD2 was the first and is the most replicated locus associated with adult IBD, to date. However, its role in pediatric onset IBD is not well understood. We performed whole-exome sequencing on a cohort of 1,183 patients with pediatric onset IBD (ages 0–18.5 years). We identified 92 probands with biallelic rare and low frequency NOD2 variants accounting for approximately 8% of our cohort, suggesting a Mendelian inheritance pattern of disease. Additionally, we investigated the contribution of recessive inheritance of NOD2 alleles in adult IBD patients from a large clinical population cohort. We found that recessive inheritance of NOD2 variants explains ~ 7% of cases in this adult IBD cohort, including ~ 10% of CD cases, confirming the observations from our pediatric IBD cohort. Exploration of EHR data showed that several of these adult IBD patients obtained their initial IBD diagnosis before 18 years of age, consistent with early onset disease. While it has been previously reported that carriers of more than one NOD2 risk alleles have increased susceptibility to Crohn’s Disease (CD), our data formally demonstrate that recessive inheritance of NOD2 alleles is a mechanistic driver of early onset IBD, specifically CD, likely due to loss of NOD2 protein function. Collectively, our findings show that recessive inheritance of rare and low frequency deleterious NOD2 variants account for 7–10% of CD cases and implicate NOD2 as a Mendelian disease gene for early onset Crohn’s Disease.

Background and Aims Timely access to approved medications is a priority in paediatric inflammatory bowel disease [IBD]. To date, the timing of drug studies in paediatric IBD has been suboptimal, with most studies conducted long after approval has been granted for adult IBD. This delay in approval leads to extensive off-label prescribing of medications in children, often without clear guidance on optimal dosing. The European Medicines Agency [EMA] and U.S. Food and Drug Administration [FDA] have implemented drug development frameworks in an attempt to address these challenges. However, access to information on these regulatory pathways in paediatric IBD is limited. We summarised the time from adult to paediatric approval of IBD therapies, outlining the regulatory approval pathway between the EMA and FDA, with the goal of identifying areas for improvement. Methods We reviewed publicly accessible data from the EMA and the FDA to identify therapeutic agents approved over 2005–2021 for paediatric IBD. Results and Conclusions Five drugs are currently approved for use in the paediatric IBD population, with long interval delays after adult approval. The impact of these drug development processes in paediatric IBD is awaited. Further consideration needs to be given to the age of enrolment along with novel, more efficient trial designs in an effort to improve access for paediatric IBD patients to newer therapies.

Background and Aims Quantifying placebo rates and the factors influencing them are essential to inform trial design. We provide a contemporary summary of clinical, endoscopic, histological and safety placebo rates in induction and maintenance clinical trials of ulcerative colitis, and identify factors influencing them. Methods MEDLINE, EMBASE and the Cochrane library were searched from April 2014 to April 2020, updating a prior meta-analysis that searched from inception to April 2014. We included placebo-controlled trials of aminosalicylates, corticosteroids, immunosuppressives, small-molecules and biologics in adults with ulcerative colitis. Placebo rates were pooled using random-effects and mixed-effects meta-regression models to assess the associated study-level. Results In 119 trials [92 induction, 27 maintenance] clinical, endoscopic and histological remission placebo rates for induction trials were 11% (95% confidence interval [CI] 9–13%), 19% [95% CI 15–23%] and 15% [95% CI 11–19%], respectively; for maintenance trials, clinical and endoscopic placebo remission rates were 18% [95% CI 12–25%] and 20% [95% CI 15–25%], respectively. Higher endoscopic subscore and a higher rate of exposure to prior biologic therapy at enrolment were associated with lower clinical and endoscopic placebo remission rates. Absence of central reading was associated with an increase in placebo endoscopic response and remission rates. More follow-up visits and increasing trial duration were associated with higher clinical placebo rates. Conclusions Placebo rates in ulcerative colitis trials vary according to the endpoint assessed, whether it is for assessment of response or remission, and whether the trial is designed for induction or maintenance. These contemporary rates across different endpoints and drug classes will help to inform trial design.

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract, of which ulcerative colitis and Crohn's disease are the 2 most prevailing entities. Very early onset IBD (VEO-IBD) children diagnosed with IBD under age 6 years. Although the etiology of IBD is mostly unknown, it involves a complex interaction among host genetics, microbiota, environmental factors, and aberrant immune responses. Advances in the understanding of the genetic contribution, which appears to be much more significant in younger children, gives us a useful insight into the pathogenesis and potential future therapeutic targets in IBD.

Background & Aims Histopathology is an emerging treatment target in ulcerative colitis (UC) clinical trials. Our aim was to provide guidance on standardizing biopsy collection protocols, identifying optimal evaluative indices, and defining thresholds for histologic response and remission after treatment. Methods An international, interdisciplinary expert panel of 19 gastroenterologists and gastrointestinal pathologists was assembled. A modified RAND/University of California, Los Angeles appropriateness methodology was used to address relevant issues. A total of 138 statements were derived from a systematic review of the literature and expert opinion. Each statement was anonymously rated as appropriate, uncertain, or inappropriate using a 9-point scale. Survey results were reviewed and discussed before a second round of voting. Results Histologic measurements collected using a uniform biopsy strategy are important for assessing disease activity and determining therapeutic efficacy in UC clinical trials. Multiple biopsy strategies were deemed acceptable, including segmental biopsies collected according to the endoscopic appearance. Biopsies should be scored for architectural change, lamina propria chronic inflammation, basal plasmacytosis, lamina propria and epithelial neutrophils, epithelial damage, and erosions/ulcerations. The Geboes score, Robarts Histopathology Index, and Nancy Index were considered appropriate for assessing histologic activity; use of the modified Riley score and Harpaz Index were uncertain. Histologic activity at baseline should be required for enrollment, recognizing this carries operational implications. Achievement of histologic improvement or remission was considered an appropriate and realistic therapeutic target. Current histologic indices require validation for pediatric populations. Conclusions These recommendations provide a framework for standardized implementation of histopathology in UC trials. Additional work is required to address operational considerations and areas of uncertainty.

Introduction For patients with a rash, the effect of teledermatology workflow on utilization has not been defined. We compared utilization across four teledermatology workflows in patients with a rash. Methods The observational longitudinal cohort study included 28,857 Kaiser Permanente Northern California members with a new rash diagnosis seen in primary care and with dermatology advice obtained using teledermatology. The workflows differed in camera and image quality; who took the picture; how the image was forwarded; and synchronicity and convenience. Results On average, 23% of patients had a follow-up office visit in dermatology within 90 days of their primary care visit. In multivariable analysis, the four technologies differed substantially in the likelihood of a follow-up dermatology office visit. In contrast, the likelihood was only negligibly related to medical centre or primary care provider. Discussion Technologies and workflows that offer the mobility of a smartphone with a high level of synchronicity in communication were associated with standardised co-management of rashes.

Background The incidence of very early onset inflammatory bowel disease (VEOIBD) is increasing, yet the phenotype and natural history of VEOIBD are not well described. Methods We performed a retrospective cohort study of patients diagnosed with VEOIBD (6 years of age and younger) between 2008 and 2013 at 25 North American centers. Eligible patients at each center were randomly selected for chart review. We abstracted data at diagnosis and at 1, 3, and 5 years after diagnosis. We compared the clinical features and outcomes with VEOIBD diagnosed younger than 3 years of age with children diagnosed with VEOIBD at age 3 to 6 years. Results The study population included 269 children (105 [39%] Crohn’s disease, 106 [39%] ulcerative colitis, and 58 [22%] IBD unclassified). The median age of diagnosis was 4.2 years (interquartile range 2.9–5.2). Most (94%) Crohn’s disease patients had inflammatory disease behavior (B1). Isolated colitis (L2) was the most common disease location (70% of children diagnosed younger than 3 years vs 43% of children diagnosed 3 years and older; P = 0.10). By the end of follow-up, stricturing/penetrating occurred in 7 (6.6%) children. The risk of any bowel surgery in Crohn’s disease was 3% by 1 year, 12% by 3 years, and 15% by 5 years and did not differ by age at diagnosis. Most ulcerative colitis patients had pancolitis (57% of children diagnosed younger than 3 years vs 45% of children diagnosed 3 years and older; P = 0.18). The risk of colectomy in ulcerative colitis/IBD unclassified was 0% by 1 year, 3% by 3 years, and 14% by 5 years and did not differ by age of diagnosis. Conclusions Very early onset inflammatory bowel disease has a distinct phenotype with predominantly colonic involvement and infrequent stricturing/penetrating disease. The cumulative risk of bowel surgery in children with VEOIBD was approximately 14%–15% by 5 years. These data can be used to provide anticipatory guidance in this emerging patient population.

ObjectivesTo determine time to diagnosis in a paediatric inflammatory bowel disease (IBD) cohort and the relative contribution of the component intervals, and to identify factors associated with diagnostic delay.DesignProspective cohort studySettingSingle-centre study including children with incident IBD at the Hospital for Sick Children diagnosed between December 2013 and December 2015.InterventionsTime to diagnosis and its subintervals were determined and patient, disease and institutional factors were tested for associations.ResultsAmong 111 children, the median overall time to diagnosis was 4.5 (IQR 2.1–8.8) months. Time to diagnosis was longer in Crohn’s disease (CD) than ulcerative colitis (UC) (median 6.8 (IQR 2.9–12.5) vs 2.4 (IQR 1.3–5.3) months) and patients with isolated small bowel disease. Twenty per cent of patients were diagnosed≥1 year after symptom onset (86% CD, 14% UC, p=0.003). Time from symptom onset to gastroenterology referral was the greatest contributor to overall time to diagnosis (median 2.9 (IQR 1.6–8.2) months). Height impairment was independently associated with diagnostic delay (OR 0.59, p=0.02, for height-for-age z-score (HAZ), signifying almost 70% increased odds of delay for every 1 SD decrease in HAZ). This height discrepancy persisted 1 year after diagnosis. Bloody diarrhoea was protective against delay (OR 0.28, p=0.02). The subinterval from referral to diagnosis was shorter in patients with laboratory abnormalities, particularly hypoalbuminaemia.ConclusionsDiagnostic delay was more common in CD and associated with height impairment that persisted 1 year after presentation. The greatest contributor to time to diagnosis was time from symptom onset to referral.

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract, of which ulcerative colitis and Crohn's disease are the 2 most prevailing entities. Very early onset IBD (VEO-IBD) children diagnosed with IBD under age 6 years. Although the etiology of IBD is mostly unknown, it involves a complex interaction among host genetics, microbiota, environmental factors, and aberrant immune responses. Advances in the understanding of the genetic contribution, which appears to be much more significant in younger children, gives us a useful insight into the pathogenesis and potential future therapeutic targets in IBD.

Purpose The timing of J-pouch surgery following colectomy for children with very early-onset colitis is controversial, with some advocating early reconstruction and others delaying reconstruction because of fear that the colitis may be owing to Crohn's disease (CD). We sought to determine the long-term incidence of CD in this population and whether there may be clinical features that predict the risk of CD. Methods Children with noninfectious colitis diagnosed prior to age 10, who underwent subtotal colectomy and ileostomy from 2000 to 2015, were reviewed. Results Twenty-five children were identified. Median age at presentation was 5.4years. Four were initially diagnosed with CD (16%), 14 with ulcerative colitis (UC) (56%), and 7 with inflammatory bowel disease unclassified (IBD-U) (28%). Eight eventually had pouch surgery. Five of the children with an initial diagnosis of UC or IBD-U developed findings that changed the diagnosis to CD at a median age of 13.4 (range 10.3 to 16.7) years. None had any indicators of CD at the initial presentation. Conclusions Approximately one quarter of patients with very early-onset colitis originally diagnosed as UC or IBD-U had a reclassification in diagnosis to CD over time. J-pouch reconstruction should be delayed until adolescence in children with very early-onset colitis. Level of Evidence 2C

Approximately 75% of children with primary sclerosing cholangitis (PSC) also have inflammatory bowel disease (IBD). IBD in patients with PSC (PSC-IBD) often has a unique phenotype, including a mild clinical course, yet it is associated with an increased risk of colorectal cancer compared with colonic IBD without PSC. We investigated whether subclinical endoscopic and histologic inflammation could account for the increased risk of colorectal cancer in patients with PSC-IBD, and whether these patients have increased fecal levels of calprotectin, a marker of inflammation.We performed a prospective study of children (age,18 y) with colonic IBD with and without PSC who underwent colonoscopy from February 1, 2016, through March 31, 2017, at the Hospital for Sick Children in Toronto, Canada. We collected pediatric ulcerative colitis activity index (PUCAI) scores (to measure symptoms) and fecal levels of calprotectin from 37 children with PSC-IBD and 50 children with only IBD (controls; UC or IBD-unclassified). Colonoscopies were scored using the Mayo endoscopic subscore and the UC Endoscopic Index of Severity (UCEIS) scores, and histologic activity was graded. Among patients in clinical remission, endoscopic scores and the odds of active endoscopic disease (based on a UCEIS score ≥1) were compared between patients with and without PSC in univariate and multivariable analyses. Correlations between activity markers were compared between groups. The ability of fecal calprotectin to identify mucosal healing in patients with PSC-IBD was assessed using receiver operating characteristic curve analyses. Analogous analyses were performed for histologic activity.Patients with PSC-IBD in clinical remission had higher endoscopic scores and greater odds of active endoscopic disease than controls (odds ratio, 5.9; 95% CI, 1.6-21.5). There was a higher degree of correlation between PUCAI and UCEIS scores in controls (r = 0.82) than in patients with PSC-IBD (r = 0.51; P = .01). Fecal levels of calprotectin correlated with UCEIS in patients with PSC-IBD (r = 0.84) and controls (r = 0.82; P = .80). Fecal levels of calprotectin identified mucosal healing in patients with PSC-IBD with an area under the receiver operating characteristic curve of 0.94 (optimal cut-point, 93 μg/g; 100% sensitivity and 92% specificity). Histologic activity scores and the odds of active histologic disease were also greater in patients in clinical remission with PSC-IBD than controls.Children with PSC-IBD in clinical remission, based on PUCAI scores, have a significantly higher risk of active endoscopic and histologic disease than children with colitis without PSC. Fecal levels of calprotectin correlate with endoscopic findings in pediatric patients with PSC-IBD; levels below 93 μg/g are associated with mucosal healing.

International audience; Herein, we report the first identification of biallelic-inherited mutations inALPIas a Mendelian cause of inflammatory bowel disease in two unrelated patients.ALPIencodes for intestinal phosphatase alkaline, a brush border metalloenzyme that hydrolyses phosphate from the lipid A moiety of lipopolysaccharides and thereby drastically reduces Toll-like receptor 4 agonist activity. Prediction tools and structural modelling indicate that all mutations affect critical residues or inter-subunit interactions, and heterologous expression in HEK293T cells demonstrated that allALPImutations were loss of function.ALPImutations impaired either stability or catalytic activity of ALPI and rendered it unable to detoxify lipopolysaccharide-dependent signalling. Furthermore, ALPI expression was reduced in patients' biopsies, and ALPI activity was undetectable in ALPI-deficient patient's stool. Our findings highlight the crucial role of ALPI in regulating host-microbiota interactions and restraining host inflammatory responses. These results indicate thatALPImutations should be included in screening for monogenic causes of inflammatory bowel diseases and lay the groundwork for ALPI-based treatments in intestinal inflammatory disorders.

Inflammatory bowel disease (IBD), clinically defined as Crohn’s disease (CD), ulcerative colitis (UC), or IBD-unclassified, results in chronic inflammation of the gastrointestinal tract in genetically susceptible hosts. Pediatric onset IBD represents ≥25% of all IBD diagnoses and often presents with intestinal stricturing, perianal disease, and failed response to conventional treatments.NOD2was the first and is the most replicated locus associated with adult IBD, to date. To determine the role ofNOD2and other genes in pediatric IBD, we performed whole-exome sequencing on a cohort of 1,183 patients with pediatric onset IBD (ages 0-18.5 years). We identified 92 probands who were homozygous or compound heterozygous for rare and low frequencyNOD2variants accounting for approximately 8% of our cohort, suggesting a Mendelian recessive inheritance pattern of disease. Additionally, we investigated the contribution of recessive inheritance ofNOD2alleles in adult IBD patients from the Regeneron Genetics Center (RGC)-Geisinger Health System DiscovEHR study, which links whole exome sequences to longitudinal electronic health records (EHRs) from 51,289 participants. We found that ~7% of cases in this adult IBD cohort, including ~10% of CD cases, can be attributed to recessive inheritance ofNOD2variants, confirming the observations from our pediatric IBD cohort. Exploration of EHR data showed that 14% of these adult IBD patients obtained their initial IBD diagnosis before 18 years of age, consistent with early onset disease. Collectively, our findings show that recessive inheritance of rare and low frequency deleteriousNOD2variants account for 7-10% of CD cases and implicateNOD2as a Mendelian disease gene for early onset Crohn’s Disease.Author SummaryPediatric onset inflammatory bowel disease (IBD) represents ≥25% of IBD diagnoses; yet the genetic architecture of early onset IBD remains largely uncharacterized. To investigate this, we performed whole-exome sequencing and rare variant analysis on a cohort of 1,183 pediatric onset IBD patients. We found that 8% of patients in our cohort were homozygous or compound heterozygous for rare or low frequency deleterious variants in the nucleotide binding and oligomerization domain containing 2(NOD2)gene. Further investigation of whole-exome sequencing of a large clinical cohort of adult IBD patients uncovered recessive inheritance of rare and low frequencyNOD2variants in 7% of cases and that the relative risk forNOD2variant homozygosity has likely been underestimated. While it has been reported that having >1NOD2risk alleles is associated with increased susceptibility to Crohn’s Disease (CD), our data formally demonstrate what has long been suspected: recessive inheritance ofNOD2alleles is a mechanistic driver of early onset IBD, specifically CD, likely due to loss of NOD2 protein function. Our data suggest that a subset of IBD-CD patients with early disease onset is characterized by recessive inheritance ofNOD2alleles, which has important implications for the screening, diagnosis, and treatment of IBD.

Xeroderma pigmentosum variant (XP-V) cells lack the damage-specific DNA polymerase eta and have normal excision repair but show defective DNA replication after UV irradiation. Previous studies using cells transformed with SV40 or HPV16 (E6/E7) suggested that the S-phase response to UV damage is altered in XP-V cells with non-functional p53. To investigate the role of p53 directly we targeted p53 in normal and XP-V fibroblasts using short hairpin RNA. The shRNA reduced expression of p53, and the downstream cell cycle effector p21, in control and UV irradiated cells. Cells accumulated in late S phase after UV, but after down-regulation of p53 they accumulated earlier in S. Cells in which p53 was inhibited showed ongoing genomic instability at the replication fork. Cells exhibited high levels of UV induced S-phase gammaH2Ax phosphorylation representative of exposed single strand regions of DNA and foci of Mre11/Rad50/Nbs1 representative of double strand breaks. Cells also showed increased variability of genomic copy numbers after long-term inhibition of p53. Inhibition of p53 expression dominated the DNA damage response. Comparison with earlier results indicates that in virally transformed cells cellular targets other than p53 play important roles in the UV DNA damage response.

Skin cancer is unique among human cancers in its etiology, accessibility and the volume of detailed knowledge now assembled concerning its molecular mechanisms of origin. The major carcinogenic agent for most skin cancers is well established as solar ultraviolet light. This is absorbed in DNA with the formation of UV-specific dipyrimidine photoproducts. These can be repaired by nucleotide excision repair or replicated by low fidelity class Y polymerases. Insufficient repair followed by errors in replication produce characteristic mutations in dipyrimidine sequences that may represent initiation events in carcinogenesis. Chronic exposure to UVB results in disruption of the epithelial structure and expansion of pre-malignant clones which undergo further genomic changes leading to full malignancy. Genetic diseases in DNA repair, xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy, show varied elevated symptoms of sun sensitivity involving skin cancers and other symptoms including neurological degeneration and developmental delays. In humans, only xeroderma pigmentosum shows high levels of cancer, but mouse strains, with any of the genes corresponding to these diseases knocked-out, show elevated skin carcinogenesis. The three major skin cancers exhibit characteristic molecular changes defined by certain genes and associated pathways. Squamous cell carcinoma involves mutations in the p53 gene; basal cell carcinoma involves mutations in the PATCHED gene, and melanoma in the p16 gene. The subsequent development of malignant tumors involves many additional genomic changes that have yet to be fully cataloged.

This study describes the introduction of Ondansetron to an established waiting room Oral Rehydration Therapy (ORT) for Emergency Department (ED) children with acute gastroenteritis, and evaluates its impact on intravenous fluid administration and admissions. Children who failed initial ORT while waiting further medical assessment received Ondansetron and ORT reattempted. Data collected over a six week period in 2009 was compared to a similar period in 2008 when children received ORT without an anti-emetic. Outcome measures included intravenous fluid administration, admission. Rates of IVF administration reduced by 19% [88/215 (40.9%) in 2008, 51/234 (21.7%) in 2009, p0.0001] with a 1.6% reduction in admission rates [31/215 (14.41%) vs 30/234(12.82%) p=0.62]. Thirty four patients received Ondansetron, 79% were successfully rehydrated orally. The addition of Ondansetron to our established ORT programme has successfully reduced rates of IVF administration and admissions in children with gastroenteritis.

Polymerase eta (pol eta) is a low-fidelity DNA polymerase that is the product of the gene, POLH, associated with the human XP variant disorder in which there is an extremely high level of solar-induced skin carcinogenesis. The complete human genomic sequence spans about 40 kb containing 10 coding exons and a cDNA of 2.14 kb; exon I is untranslated and is 6 kb upstream from the first coding exon. Using bacterial artificial chromosomes (BACs), the gene was mapped to human chromosome band 6p21 and mouse band 17D. The gene is expressed in most tissues, except for very low or undetectable levels in peripheral lymphocytes, fetal spleen, and adult muscle; exon II, however, is frequently spliced out in normal cells and in almost half the transcripts in the testis and fetal liver. Expression of POLH in a multicopy episomal vector proved nonviable, suggesting that overexpression is toxic. Expression from chromosomally integrated linear copies using either an EF1-alpha or CMV promoter was functional, resulting in cell lines with low or high levels of pol eta protein, respectively. Point mutations in the center of the gene and in a C-terminal cysteine and deletion of exon II resulted in inactivation, but addition of a terminal 3 amino acid C-terminal tag, or an N- or C-terminal green fluorescent protein, had no effect on function. A low level of expression of pol eta eliminated hMre11 recombination and partially restored UV survival, but did not prevent UV-induced apoptosis, which required higher levels of expression. Polymerase eta is therefore involved in S-phase checkpoint and signal transduction pathways that lead to arrest in S, apoptosis, and recombination. In normal cells, the predominant mechanism of replication of UV damage involves pol eta-dependent bypass, and Mre11-dependent recombination that acts is a secondary, backup mechanism when cells are severely depleted of pol eta.