Background and AimsAn expanding number of monogenic defects have been identified as causative of severe forms of very early-onset inflammatory bowel diseases [VEO-IBD]. The present study aimed at defining how next-generation sequencing [NGS] methods can be used to improve identification of known molecular diagnosis and to adapt treatment.MethodsA total of 207 children were recruited in 45 paediatric centres through an international collaborative network [ESPGHAN GENIUS working group] with a clinical presentation of severe VEO-IBD [n = 185] or an anamnesis suggestive of a monogenic disorder [n = 22]. Patients were divided at inclusion into three phenotypic subsets: predominantly small bowel inflammation, colitis with perianal lesions, and colitis only. Methods to obtain molecular diagnosis included functional tests followed by specific Sanger sequencing, custom-made targeted NGS, and in selected cases whole exome sequencing [WES] of parents-child trios. Genetic findings were validated clinically and/or functionally.ResultsMolecular diagnosis was achieved in 66/207 children [32%]: 61% with small bowel inflammation, 39% with colitis and perianal lesions, and 18% with colitis only. Targeted NGS pinpointed gene mutations causative of atypical presentations, and identified large exonic copy number variations previously missed by WES.ConclusionsOur results lead us to propose an optimised diagnostic strategy to identify known monogenic causes of severe IBD.

BackgroundThe frequency of primary resistance to antibiotics in H. pylori isolates is increasing worldwide. In Tunisia, there are limited data regarding the pattern of H. pylori antibiotic primary resistance.AimTo evaluate the primary resistance of H. pylori to clarithromycin, metronidazole and amoxicillin and to detect the mutations involved in clarithromycin resistance.Materials and methods273 strains isolated from adults and children were enrolled. The primary resistance to clarithromycin, metronidazole and amoxicillin was evaluated by means of E-test minimal inhibitory concentration (MIC). The real-time PCR using Scorpion primers was performed in all cases to assess clarithromycin primary resistance and point mutations involved.ResultsNo resistance to amoxicillin was detected. For adults, resistance to clarithromycin and metronidazole was found respectively in 14.6% and 56.8%, and respectively in 18.8% and 25% in children. Overall, the rates of global primary resistance to clarithromycin and metronidazole in Tunisia were respectively determined in 15.4% and 51.3%.By the use of Scorpion PCR, the A2143G was the most frequent point mutation observed (88.1%), followed by the A2142G (11.9%); the A2142C was not found and 18 of 42 patients (42.8%) were infected by both the resistant and the susceptible genotype.The association of clarithromycin resistance with gender was not statistically significant, but metronidazole resistant strains were isolated more frequently in females (67.8%) than in males (32.2%) and the difference was significant. As for gastroduodenal diseases, the difference between strains isolated from patients with peptic ulceration and those with non peptic ulceration was not statistically significant. When about the distribution of resistant strains to clarithromycin and metronidazole between the three Tunisian cities (Tunis, Menzel Bourguiba and Mahdia), the difference was not statistically significant.ConclusionLocal data regarding the primary resistance of H. pylori to clarithromycin, metronidazole and amoxicillin and the main genetic mutation involved in clarithromycin resistance in vivo (A2143G) are necessary to prove a clear need for a periodic evaluation of antibiotic consumption and new therapeutic strategies in Tunisia in order to avoid the emergence of resistant strains.

This work aims to estimate celiac disease prevalence in school-children in the island of Djerba and assess rapid method feasibility for screening. We screened 2064 schoolchildren by a rapid method to detect IgA anti-tissue transglutaminase and IgA deficiency. Children with positive results were tested for IgA anti-transglutaminase and anti-endomysium by conventional tests. In positive children, intestinal biopsy was performed. IgA deficiency suspected by rapid method was confirmed by nephelometry. In these cases IgG anti-endomysium was performed. Rapid test was positive in 7 children; conventional serology was positive in all and 6 of them accepted the biopsy. Total villous atrophy was observed in 5 while intestinal mucosa was normal in one. Among children with positive serology, 3 had silent form, 1 chronic diarrhea, one growth failure and 2 had borderline growth. IgA deficiency was suspected in 13 cases and was confirmed in 11 children tested. Prevalence of celiac disease was 0.24-0.34% and that of IgA deficiency 0.5-0.6%. This screening study confirms that celiac disease is relatively common in schoolchildren in Tunisia. It confirms also that even those with symptoms typical for celiac disease escape diagnosis. Rapid test is better accepted by parents and children than test requiring a venous blood sample.

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