Diagnostic Yield of Next-generation Sequencing in Very Early-onset Inflammatory Bowel Diseases: A Multicentre Study.

BACKGROUND AND AIMS: An 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. METHODS: A 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. RESULTS: Molecular 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. CONCLUSIONS: Our results lead us to propose an optimised diagnostic strategy to identify known monogenic causes of severe IBD.

Lack of Accuracy of Biomarkers and Physical Examination to Detect Bacterial Infection in Febrile Infants.

OBJECTIVES: The aim of this study was to analyze the usefulness of physical examination, C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and absolute neutrophils counts (ANCs) for the diagnosis of invasive bacterial infections (IBIs) and potentially serious bacterial infections in infants younger than the age of 3 months presenting with fever without source (FWS) to the emergency department (ED). METHODS: A descriptive retrospective study that includes all infants aged younger than 3 months who presented with FWS to the ED between July 2008 and January 2012. We evaluated diagnostic performance for each test by receiver operating characteristic curve analysis. Sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were also calculated. RESULTS: Three hundred eighteen patients met the inclusion criteria. Eleven bacteremia (3.5%) and 76 urinary tract infections (23.9%) were diagnosed. To detect IBI, the areas under the curve for the different tests were as follows: PCT, 0.77 (95% confidence interval [CI], 0.57-0.96); CRP, 0.54 (95% CI, 0.36-0.73); ANC, 0.53 (95% CI, 0.34-0.71); and WBC, 0.42 (0.24-0.61). To detect potentially serious bacterial infections, the areas under the curve were as follows: PCT, 0.66 (95% CI, 0.59-0.74); CRP, 0.68 (0.60-0.76); ANC, 0.64 (0.56-0.71); and WBC, 0.66 (0.58-0.72). CONCLUSIONS: Procalcitonin is better than CRP, WBC, and ANC to confirm or dismiss the presence of an IBI in infants aged younger than 3 months presenting with FWS to the ED. However, it could not identify almost 30% of infants with IBI. Most patients diagnosed with IBI (10 of 11) presented abnormal values in at least one of the analytical parameters and/or physical appearance. Four of 5 patients with IBI and well appearing presented abnormal results in at least one of the analytical parameters. Therefore, the development of tools combining different tests including the new biomarkers could increase the reliability of the tests for the diagnosis of IBI in these patients.