Celiac disease (CD) is an autoimmune disorder in which gluten causes damage to the villi in the small intestine. It is one of the most common food intolerances in western populations. CD is characterized by a chronic inflammation of the small intestinal mucosa that may result in atrophy of intestinal villi, malabsorption, and a variety of clinical manifestations. Up to now the only treatment is a lifelong, gluten-free diet, which in most cases results in complete disappearance of the symptoms. Genetic components play a major role in the induction and manifestation of CD. HLA-DQ2.5 and HLA-DQ8 are important genetic risk factors, from which HLA-DQ2.5 shows the strongest association with a predisposition to CD. In contrast to 30-40% of the general population, around 95.98% of the CD patients carry this HLA type. HLA-DQ2.5 and HLA-DQ8 have a strong negative predictive value, as individuals with no HLA-DQ2 or DQ8 have almost no risk of developing CD. Amongst people positive for HLA-DQ2 or DQ8 only 3% will develop clinically recognized celiac disease.