Targeted Gene Panel Sequencing for Early-onset Inflammatory Bowel Disease and Chronic Diarrhea

Background: In contrast to adult-onset inflammatory bowel disease (IBD), where many genetic loci have been shown to be involved in complex disease etiology, early-onset IBD (eoIBD) and associated syndromes can sometimes present as monogenic conditions. As a result, the clinical phenotype and ideal disease management in these patients often differ from those in adult-onset IBD. However, due to high costs and the complexity of data analysis, high-throughput screening for genetic causes has not yet become a standard part of the diagnostic work-up of eoIBD patients. Methods: We selected 28 genes of interest associated with monogenic IBD and performed targeted panel sequencing in 71 patients diagnosed with eoIBD or early-onset chronic diarrhea to detect causative variants. We compared these results to whole-exome sequencing (WES) data available for 25 of these patients. Results: Target coverage was significantly higher in the targeted gene panel approach compared with WES, whereas the cost of the panel was considerably lower (approximately 25% of WES). Disease-causing variants affecting protein function were identified in 5 patients (7%), located in genes of the IL10 signaling pathway (3), WAS (1), and DKC1 (1). The functional effects of 8 candidate variants in 5 additional patients (7%) are under further investigation. WES did not identify additional causative mutations in 25 patients. Conclusions: Targeted gene panel sequencing is a fast and effective screening method for monogenic causes of eoIBD that should be routinely established in national referral centers.info:eu-repo/semantics/publishedVersio

At the bottom of the differential diagnosis list: unusual causes of pediatric hypertension

Hypertension affects 1–5% of children and adolescents, and the incidence has been increasing in association with obesity. However, secondary causes of hypertension such as renal parenchymal diseases, congenital abnormalities and renovascular disorders still remain the leading cause of pediatric hypertension, particularly in children under 12 years old. Other less common causes of hypertension in children and adolescents, including immobilization, burns, illicit and prescription drugs, dietary supplements, genetic disorders, and tumors will be addressed in this review

New developments in serodiagnosis of childhood celiac disease: assay of antibodies against deamidated gliadin.

Antibodies to deamidated gliadin present a new tool in the diagnosis of celiac disease (CD). In children, the ELISA for the determination of IgG antibodies to (deamidated) gliadin-analogous fusion peptides (GAF3X) has a superior performance compared to the ELISA for the determination of antibodies against native gliadin and is comparable to assays for IgA antibodies against tissue transglutaminase (IgA-anti-tTG). The combined investigation of IgG antibodies to GAF3X (IgG-anti-GAF3X) and IgA-anti-tTG significantly increases the fraction of children definitely identified as either CD or non-CD patients. The new IgG-anti-GAF3X ELISA was also able to detect CD in three cases of IgA deficiency and in two cases of latent CD and was also useful in the diagnosis of children younger than 2 years of age

Antibody concentrations decrease 14-fold in children with celiac disease on a gluten-free diet but remain high at 3 months

Background and Aims Celiac disease can be identified by a serologic test for IgA against tissue transglutaminase (IgA-TTG) in a large proportion of children. However, the increased concentrations of antibody rarely normalize within the months after children are placed on a gluten-free diet (GFD). Early serologic predictors of sufficient adherence to gluten-free diet are required for optimal treatment. Methods In a prospective study, we observed the response to a GFD in 345 pediatric patients (67% girls; mean age, 8.4 y) who underwent duodenal biopsy to confirm or refute celiac disease from October 2012 through December 2015. Baseline serum samples were tested centrally for IgA-TTG and IgG against deamidated gliadin. Follow-up serologic analyses of children on a GFD were performed about 3 months later. Results The geometric mean concentration of IgA-TTG decreased from 72.4-fold to 5.2-fold the upper limit of normal (ULN), or by a factor of 14.0 (95% CI, 12.0–16.4). A substantial response (defined as a larger change than the typical variation in patients not on a GFD) was observed in 80.6% of the children. Only 28.1% of patients had a substantial response in the concentration of IgG against deamidated gliadin. Concentration of IgA-TTG remained above 1-fold the ULN in 83.8% of patients, and above 10-fold the ULN in 26.6% of patients with a substantial response. Conclusions Serum concentration of IgA-TTG decreases substantially in most children with celiac disease within 3 months after they are placed on a GFD, but does not normalize in most. This information on changes in antibody concentrations can be used to assess patient response to the diet at short-term follow-up evaluations. Patients with a substantial response to a GFD often still have high antibody levels after 3 months. German Clinical Trials Registry no. DRKS00003854

Antibody concentrations decrease 14-fold in children with celiac disease on a gluten-free diet but remain high at 3 months

Background & Aims Celiac disease can be identified by a serologic test for IgA against tissue transglutaminase (IgA-TTG) in a large proportion of children. However, the increased concentrations of antibody rarely normalize within the months after children are placed on a gluten-free diet (GFD). Early serologic predictors of sufficient adherence to gluten-free diet are required for optimal treatment. Methods In a prospective study, we observed the response to a GFD in 345 pediatric patients (67% girls; mean age, 8.4 y) who underwent duodenal biopsy to confirm or refute celiac disease from October 2012 through December 2015. Baseline serum samples were tested centrally for IgA-TTG and IgG against deamidated gliadin. Follow-up serologic analyses of children on a GFD were performed about 3 months later. Results The geometric mean concentration of IgA-TTG decreased from 72.4-fold to 5.2-fold the upper limit of normal (ULN), or by a factor of 14.0 (95% CI, 12.0–16.4). A substantial response (defined as a larger change than the typical variation in patients not on a GFD) was observed in 80.6% of the children. Only 28.1% of patients had a substantial response in the concentration of IgG against deamidated gliadin. Concentration of IgA-TTG remained above 1-fold the ULN in 83.8% of patients, and above 10-fold the ULN in 26.6% of patients with a substantial response. Conclusions Serum concentration of IgA-TTG decreases substantially in most children with celiac disease within 3 months after they are placed on a GFD, but does not normalize in most. This information on changes in antibody concentrations can be used to assess patient response to the diet at short-term follow-up evaluations. Patients with a substantial response to a GFD often still have high antibody levels after 3 months. German Clinical Trials Registry no. DRKS00003854

Validation of antibody-based strategies for diagnosis of pediatric celiac disease without biopsy.

Background and aims Diagnosis of coeliac disease (CD) uses clinical, genetic, serological and duodenal morphological findings. Recent paediatric guidelines, based largely on retrospective data, suggest omitting biopsies if the concentration of IgA-antibodies to tissue transglutaminase (IgA-aTTG) exceeds 10-times the upper limit of normal (10×ULN) and if further criteria are met. In a retrospective study, we proposed two diagnostic procedures based on (a) IgA-aTTG and total IgA and (b) IgA-aTTG and IgG-antibodies to deamidated gliadin. They use both one- and tenfold ULN, assigning the classification “CD”, “non-CD” or “biopsy required”. The prospective multicentre AbCD study validates the positive/negative predictive values (PPV/NPV) of these procedures. Methods Thirteen centres from Germany, United Kingdom and Austria enrolled paediatric patients scheduled for duodenal biopsy to confirm or rule out CD. Antibodies were measured by a blinded laboratory and tissue sections underwent reference pathology. After follow-up, the treating paediatrician chose the diagnosis “CD”, “non-CD” or “no final diagnosis possible”. Results For 898 of 949 participants, serum, biopsy, and follow-up data were available (592 CD, 345 non-CD, 24 no final diagnosis). The PPV/NPV of the two procedures were 0.988/0.934 and 0.988/0.958. Model-based extrapolation shows that PPV/NPV remain above 0.95 even at a prevalence as low as 4%. Endomysium antibodies and HLA-typing did not improve PPV in samples with IgA-aTTG ≥10×ULN. Notably, the discrepancy rate between pathologists is 4.2% and comparable to the error rate in the serological procedures. Conclusions The procedures allow reliable diagnosis or exclusion of CD without biopsy in a substantial proportion of children who present at the paediatric gastroenterologist with the test kits examined.</p