This study, published in *Gastroenterology* by Van Limbergent et al. (2008), investigates the phenotypic characteristics of childhood-onset inflammatory bowel disease (IBD) and compares them with adult-onset IBD. The research involved 416 patients with childhood-onset IBD (276 Crohn's disease [CD], 99 ulcerative colitis [UC], 41 IBD type unclassified [IBDU]) and 1297 patients with adult-onset IBD (596 CD, 701 UC). Using the Montreal classification, the study found that at diagnosis, CD in children often involved the small bowel and colon (L3), colon (L2), and ileum (L1), with 51% of cases also affecting the upper gastrointestinal (GI) tract (L4). Within 2 years, 39% of children experienced an increase in disease extent. Behavioral characteristics progressed rapidly, with 24% of children developing stricturing or penetrating complications within 4 years. Compared to adults, childhood-onset disease was characterized by a "panenteric" phenotype (ileocolonic plus upper GI involvement) and less isolated ileal or colonic disease. UC was extensive in 82% of children at diagnosis, and 46% progressed to extensive colitis during follow-up. The study also found that 46% of children with CD and 35% with UC required immunomodulatory therapy within 12 months of diagnosis. The median time to first surgery was longer in childhood-onset CD (13.7 years) compared to adult-onset CD (7.8 years), while the reverse was true for UC. The findings suggest that childhood-onset IBD is characterized by extensive intestinal involvement and rapid early progression.This study, published in *Gastroenterology* by Van Limbergent et al. (2008), investigates the phenotypic characteristics of childhood-onset inflammatory bowel disease (IBD) and compares them with adult-onset IBD. The research involved 416 patients with childhood-onset IBD (276 Crohn's disease [CD], 99 ulcerative colitis [UC], 41 IBD type unclassified [IBDU]) and 1297 patients with adult-onset IBD (596 CD, 701 UC). Using the Montreal classification, the study found that at diagnosis, CD in children often involved the small bowel and colon (L3), colon (L2), and ileum (L1), with 51% of cases also affecting the upper gastrointestinal (GI) tract (L4). Within 2 years, 39% of children experienced an increase in disease extent. Behavioral characteristics progressed rapidly, with 24% of children developing stricturing or penetrating complications within 4 years. Compared to adults, childhood-onset disease was characterized by a "panenteric" phenotype (ileocolonic plus upper GI involvement) and less isolated ileal or colonic disease. UC was extensive in 82% of children at diagnosis, and 46% progressed to extensive colitis during follow-up. The study also found that 46% of children with CD and 35% with UC required immunomodulatory therapy within 12 months of diagnosis. The median time to first surgery was longer in childhood-onset CD (13.7 years) compared to adult-onset CD (7.8 years), while the reverse was true for UC. The findings suggest that childhood-onset IBD is characterized by extensive intestinal involvement and rapid early progression.