IMMUNOLOGY: Edited by Jocelyn A. SilvesterEvaluation of very early-onset inflammatory bowel diseasede Mesquita, Mirjam Buenoa,b; Shouval, Dror S.a,b,cAuthor Information aPediatric Gastroenterology Unit, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Ramat Gan bSackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel cVEO-IBD International Consortium Correspondence to Dror S. Shouval, MD, MMSc, Pediatric Gastroenterology Unit, Attending Physician, Pediatric Gastroenterology Lab, Principal Investigator, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Ramat Gan, 5262100, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel. Tel: +972 3 5305006; fax: +972 3 5302883; e-mail: firstname.lastname@example.org Current Opinion in Gastroenterology: November 2020 - Volume 36 - Issue 6 - p 464-469 doi: 10.1097/MOG.0000000000000680 Buy Metrics Abstract Purpose of review Very early-onset inflammatory bowel disease (VEO-IBD) is a rare presentation defined as onset of intestinal inflammation at the age of <6 years. Some of these young children develop IBD because of inherent defects in immune or epithelial cell function resulting from deleterious mutations in genes involved in mucosal homeostasis. Here, we provide an overview of the clinical, genetic and immunologic approach in patients with VEO-IBD. Recent findings More than 50 different monogenic disorders directly causing IBD have been identified in the last decade; most of them present with unique clinical features in the first years of life. Such a diagnosis may facilitate the administration of targeted therapies and is important for genetic counseling. Nevertheless, a monogenic disorder is identified only in a minority of patients with VEO-IBD. Consequently, different demographic, clinical and histologic features should prompt a detailed genetic and immunologic workup in patients with IBD. Summary A diagnosis of monogenic IBD can have a huge impact on patient's care, enabling in some cases to provide personalized therapies. Clinicians should be aware of unique features of such disorders, and complete a detailed genetic and immune workup in selected cases, even when disease manifests beyond a young age. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.