Celiac disease is strongly associated with specific types or alleles of HLA-DQA1 and HLA-DQB1. These two genes encode two human leukocyte antigens, which are important components of the human immune system. The celiac-associated alleles are HLA-DQA1*05, HLA-DQB1*02 and HLA-DQB1*0302. Individuals that have one or more of these alleles have an increased risk of developing celiac disease.
However, this is not a diagnostic test, as only a subset of people with these alleles will develop celiac disease. If these alleles are absent, the diagnosis of celiac disease can essentially be excluded, as there is a less than 0.04% chance of developing celiac disease in people that don’t have one or more of these at-risk alleles.