Coeliac disease (pronounced SEE-lee-ak) is an autoimmune disease. In people with coeliac disease, the lining of the small bowel is damaged by even tiny amounts of gluten. Gluten is a protein found in grains such as wheat, rye, barley and oats. Coeliac disease affects people of all ages and genders. It runs in families and can develop at any age from infancy to adulthood. Currently, the only available treatment is with a gluten-free diet. Early diagnosis and treatment of coeliac disease significantly reduces the risk of most complications. You should tell family who share your genes (parents or siblings) that you have coeliac disease. They can also be tested.