Is Celiac Disease Genetic ?

Many celiac patients wonder whether their disease is congenital or developed.

Celiac is an autoimmune and multifactorial disease that develops against gluten protein; this means that multiple genes interact with environmental factors (gluten intake, infections, intestinal diseases, diet) to cause celiac disease. Key genes involved in the risk of developing celiac disease are the Human Leukocyte Antigen (HLA) genes. The interaction of genes and environmental factors is due to the interaction of the HLA-DQA1 and HLA-DQB1 genes. HLA-DQ2 and/or HLA-DQ8 genes, which play a role in the development of celiac disease, are formed as a result of the specialization of HLA-DQA1 and HLA-DQB1 gene pairs.

 Inherited HLA-DQ2 and/or HLA-DQ8 genes are necessary but not sufficient for the development of celiac disease. 30-40% of the population has one of the celiac-related human HLA genes that cause susceptibility to the HLA-DQ2 and/or HLA-DQ8 genes, but only 1% to 3% of people with either or both develop celiac disease. Therefore, having this gene or genes does not mean that a person has or will have celiac disease. About 95% of individuals with celiac disease have the HLA-DQ2 gene, and most of the remaining 5% have the HLA-DQ8 gene.

 The HLA-DQ2 celiac disease susceptibility gene is either dominantly or recessively carried in the genes of the parents. Whether this gene is dominant or recessive differs from person to person. The HLA-DQ8 susceptibility gene for celiac disease is predominantly inherited. However, even if a child inherits the HLA-DQ2 and/or HLA-DQ8 genes, that is, their predisposition to celiac disease, this does not mean that the child has or will have celiac disease. A predisposition to celiac disease may be inherited, but the disease itself is not inherited.

Genetic Predisposition Alone Is Not Enough! 

Genetic predisposition to celiac disease alone is not sufficient for the onset of the disease. Genetic predisposition, environmental factors (gluten intake) and changes in other genes trigger a series of immunological processes that cause the development of celiac disease in genetically predisposed individuals. In addition to these three basic points, diseases such as type 1 diabetes and autoimmune thyroid disease increase the likelihood of developing celiac disease. 

First Degree Relatives Attention! 

Celiac disease is genetically based, so it is more common among individuals with a family history of celiac disease. If any individual has a first-degree relative with celiac disease, that individual has an increased risk of developing celiac disease. This condition is seen in 5-10% of family members of individuals diagnosed with celiac disease. Individuals with a family history of celiac disease are recommended to undergo necessary screenings against the risk of developing celiac disease. Especially in childhood, the right growth and development curve can be caught with early diagnosis. Therefore, screening first-degree relatives for celiac disease is important for early diagnosis.

Is Continuous Scanning Necessary? 

It should be noted that celiac disease can develop at any age with various symptoms. Individuals with a family history of celiac disease are recommended to have screening tests against the risk of developing celiac disease. The Human leukocyte antigen (HLA) gene test, one of the celiac disease screening tests, can tell whether individuals will develop celiac. Individuals screened for human leukocyte antigen gene testing will not develop celiac disease if their HLA gene tests yield negative results. For this reason, first of all, screening for the HLA gene test can prevent continuous screening. Although the HLA gene test is negative, it should always be kept in mind that there is always a small risk. It is wrong to directly diagnose celiac disease in individuals with a positive HLA gene test. 

These individuals should apply for diagnostic and screening tests such as blood test, tissue tranglutaminase test, deamide gliadin peptides test, total IgA measurement, biopsy used in the diagnosis of celiac disease. If the result of all these scans is negative, it can be said that the individual does not have celiac disease, but there is a risk of developing celiac disease in the future. Individuals with a genetic predisposition are always at risk. For this reason, it is recommended that individuals with a family history of celiac disease and genetically predisposed should be screened every 3-5 years in terms of the risk of developing celiac disease. During this process, if the individual suspects any condition related to celiac disease, they can apply for these tests again in a shorter time. 

Dietitian Can KOCAKURT