9323. Genetics. Celiac disease

Celiac disease is a genetically determined autoimmune disease in which gluten consumption leads to a chronic inflammatory process in the gastrointestinal tract. It is an inherited condition associated with the inheritance of specific genes responsible for the recognition of gluten by molecules of the major histocompatibility complex (HLA).

The main genetic markers of celiac disease are the HLA-DQ8 and HLA-DQ2 protein complexes, which are involved in the presentation of gluten antigens to T cells of the immune system. This leads to an immune attack on the mucous membrane of the small intestine, causing villous atrophy and impaired nutrient absorption. Symptoms of the disease include diarrhea, weight loss, steatorrhea, iron-deficiency anemia, skin rash, drowsiness, and bloating.

The test is used to identify genetic predisposition and diagnose celiac disease in patients with symptoms, negative or equivocal results of other celiac disease tests, and in people following a gluten-free diet.

It is recommended to perform this test in combination with testing for IgA and IgG antibodies to tissue transglutaminase and/or deamidated gliadin peptides and endomysium.

The different types of HLA expressed in humans are genetically determined.

HLA-DQ2 is found in 25–30% of the general population.

HLA-DQ8 is present in 5–10% of people.

The DQ2.5 haplotype is closely associated with celiac disease, whereas DQ2.2 has a weaker influence on disease development. These serotypes are significantly more prevalent among patients with celiac disease because they play an important role in the mechanism of gluten presentation to T cells of the immune system.

ESPGHAN (European Society for Paediatric Gastroenterology, Hepatology and Nutrition) recommends HLA testing in asymptomatic patients who are at high risk of celiac disease. NICE (National Institute for Health and Care Excellence) recommends HLA typing only in specific cases.

A positive HLA-DQ2/DQ8 result indicates an increased risk of developing celiac disease. A negative result does not exclude the disease, as these serotypes may not be detected in some patients with celiac disease.

Detection of the DQ2/DQ8 genetic markers has important diagnostic value and is included in the ESPGHAN (European Society for Paediatric Gastroenterology, Hepatology and Nutrition) diagnostic protocol for assessing genetic predisposition to celiac disease and prior to endoscopic examination.

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: