Although the precise etiology of inflammatory bowel disease (IBD) is still unknown, over the last decade active research allowed to gain more precise insights in the pathophysiology of IBD indicating that the chronic inflammation of the intestinal mucosa is directed against the microbiota of the gut in particularly susceptible individuals. Genetic studies and more recently genome-wide association studies (GWAS) have allowed to identify over 70 susceptibility genes which confer an increased risk of developing IBD. In the last years the attention of researchers has shifted to the identification of the early immunological changes that occur already at a preclinical stage of the disease, trying also at identifying the disease before it shows itself. Recently, the ability of a combination of serological markers in predicting the development of IBD has been demonstrated in adults. However, there are no studies evaluating a cohort of children at high risk for the disease, in whom the first immunological changes underlying the development of IBD could be studied, including a combination of genetic, serological, fecal and clinical markers.

The purpose of this study is to evaluate in a population genetically well-characterized, as siblings and twins of patients affected with IBD, early genetic, serologic, fecal and clinical markers of disease, which may be present even years before developing the disease. The identification of these markers in predisposed individuals could help to implement strategies for prevention or early treatment to modify the natural history of IBD.

This is a multicenter, prospective, study evaluating the role of serological, genetic, fecal and clinical markers in predicting the development of IBD in a high risk population. The study will be divided in two phases. In the first phase the prevalence of genetic, serologic, fecal, clinical risk factors in 100 siblings of children affected with IBD compared to 100 healthy children with no family history for IBD will be evaluated. The estimated duration of the first phase of the study is 12 months. In a second phase, a long-term follow-up (5 years) will be performed in order to evaluate the accidental cases of IBD in this population.

Inclusion Criteria:

• siblings of children affected with IBD
• children without a family history of IBD

Exclusion Criteria:

• age > 18 years
• age < 6 years
• concomitant autoimmune disorders