The inflammatory bowel diseases (or I.B.D. )are crhonical diseases that cause inflammation of the intestines and don’t establish an increase of mortality, but due of they recurring and intermittent activity determine a great negative impact on the quality of the life and the social abitily of who is affected.

Inside this group of pathology we must distinguish between two different fields :

• Crohn's disease
• Ulcerative colitis

Although the diseases have some features in common, there are some important differences. Both interested young individuals , between 15 and 40 years old but Crohn's disease differs from ulcerative colitis in the areas of the bowel it involves - it most commonly affects the last part of the small intestine (called the terminal ileum) and parts of the large intestine whereas ulcerative colitis affects only the lining of the bowel and doesn’t involve the entire bowel wall.

They are rare and medical research hasn't determined yet what causes inflammatory bowel disease. They differs from the risk of surgery , who is higher in the Crohn's disease but surgical procedures for ulcerative colitis and Crohn's disease are quite different.

In the case of ulcerative colitis, removal of the colon (large intestine) may be necessary.
Their frequency is about 1-2‰ (or 100-200 cases every 100.000 inhabitants 100.000) but in Italy there aren’t studies adequately reliables. In Piemonte on 2004 there were registered more than 2.300 patients affected by I.B.D. and extending this research to all the Italian country we can estimate that there are about 100-150.000 patients affected by this diseases.

Since years we know that exist a familiarity in the IBD’s distribution , between first degree’s relatives there is an increased risk of observing disease’s cases compared to a group of unrelated patients.

However this increase of the risk (about 10 times higher that the standard risk of the population) entail an increase of the IBD only around 1%.
The family component’s contribution to the risk to develop IBD is equal or higher to the cardiovascular or diabetes’ ones, that are considered strongly characterized by heredity.
The observation of a remarkable concordance of the progress and the type of disease between identical twin brothers suggested that there was a genetic aptitude to develop these diseases.

More recently other genetic studies picked out that there are some genetic features that associated themselves to the IBD and when presents they increase the risk of development of these diseases.

However the genetic aptitude represent only a part of the problem, since for example there is the possibility that monozygotic twins don’t have the same development of the disease in spite of the identity of their gene pool.

The more accepted disease model is the one that includes the existence of a genetic substratum that predispose the development of the disease and the exposure to environmental factors that are not well known (smoke, bacterial flora,….), together with an immune structure favourable to the maintaining of the infection in a pathological way.

Next to these factors that determine the IBD there are combinations of genes and secondary environmental factors that contribute to determine a particular type of disease.

The text brings out that the IBD are inflammatory diseases with a considerable costs for the patient and the society , related to the medical and surgical ‘s treatment costs but also linked to the reduction of the social and working capacity and the life’s quality of the patients and their relatives.

For this reason is important that the research and the technology about these diseases could progress in order to improve the knowledge about the IBD and the treatment efficacy and permit the diffusion of less invasive diagnostic techniques.