The purpose of the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry is to study the contemporary natural history of children <16 years of age newly diagnosed with inflammatory bowel disease. The project follows these children quarterly from diagnosis examining clinical, laboratory, and humanistic outcomes. Genetic and serologic monitoring is performed on the study population.

Observations of children with IBD often suggest a more severe course than that found in adults. Explanations for this are unclear, especially since children are less likely to engage in some behaviors (e.g., smoking) that may have a deleterious effect on disease course as noted in adults. In many ways children are a better "experimental model" of IBD because they don't have as many confounding medical factors as adults. Both Crohn's disease and ulcerative colitis are believed to result from a complex interaction of genetic and environmental factors (1). Recently, the gene CARD15/NOD2 on chromosome 16 has been identified in approximately 25% of Caucasian patients with Crohn's disease and is felt to be a significant predisposing factor to the development of fibrostenosing disease (2). Additionally, seropositivity for perinuclear antinuclear cytoplasmic factor (pANCA) has been demonstrated much more frequently in patients with ulcerative colitis than in those with Crohn's disease, while anti-Saccharomyces antibody (ASCA) is more common in the latter population (3). The importance of these serological abnormalities is not clear, though some data suggest an influence on the development of complications.

Our hypothesis is that phenotypic, genotypic and serologic characteristics may provide prognostic information on response to therapy and course in children with IBD. This type of prognostic information is particularly important as newer therapies are developed.

Inclusion Criteria:

1. Definite diagnosis of ulcerative colitis, Crohn's disease, indeterminate colitis
2. Age up to 16 years and zero days at time of diagnosis
3. Informed consent/assent from parent/guardian and patient
4. Ability to be available for regular follow-up visits

Exclusion Criteria:

1. Diagnosis of IBD greater than 1 month prior to presentation to participating center
2. Age greater than 16 years and zero days
3. Inability to be available for regular follow-up visits

Children <16 years old with inflammatory bowel disease