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In the debate of nature vs. nurture, where does autoimmune disease fall?
Many autoimmune diseases are complex in origin, with both environmental and genetic factors at play.
One of these is celiac disease—an autoimmune condition in which the immune system reacts to gliadin, the alcohol-soluble portion of gluten. Gliadin can be found in grains such as wheat, rye, and barley.
Experts estimate that about two million people in the US, or one percent of the population, have celiac disease.
The condition is serious and, when left undiagnosed, can cause severe symptoms such as profound malabsorption, steatorrhea, wasting, and chronic inflammation.
Additionally, there are associations between celiac disease and other major conditions such as Type I diabetes mellitus, thyroid disease, and other autoimmune diseases.
Celiac disease development is linked to both genetic and environmental factors and can occur at any age. In this article, we’ll focus on the genetic component of celiac, and discuss which genes are associated with it.
What Genes Are Involved in Celiac Development?
Many individuals with celiac disease carry one of two genes: Human leukocyte antigen (HLA) DQ2 and DQ8. However, it’s possible (but extremely rare) to develop the disease without either gene.
The genes are a part of the Human Leukocyte Antigen gene family, which helps the immune system distinguish between the body’s own proteins and foreign proteins.
There is no known difference in the severity of celiac between those with the HLA-DQ2 gene and those with the HLA-DQ8 gene.
An individual with only the HLA-DQ2 or the HLA-DQ8 gene has a 10% and 8% chance of developing celiac, respectively.
Conversely, someone that carries both the HLA-DQ2 and HLA-DQ8 genes has a 14% chance of developing celiac.
It's important to note that although the chances of developing celiac without the HLA-DQ2 or HLA-DQ8 genes are slim, according to the latest research, non-celiac gluten sensitivity can still cause increased intestinal permeability, as well as intestinal cell damage and chronic inflammation.
How Do Celiac Genes Work?
The HLA-DQ2 and HLA-DQ8 genes create proteins that bind together to form a functional complex called an antigen-binding DQαβ heterodimer. This complex can be found on the surface of specific immune system cells and latches onto peptides outside the cell. If the immune system perceives these peptides as not belonging to the body, like viral or bacterial peptides, it triggers an immune response to attack the particles it deems foreign.
Ideally, gluten should not trigger this immune response—celiac results from the immune system confusing gliadin for a dangerous foreign invader and setting off an internal alarm system. The antigen-binding DQαβ heterodimer reacts immediately to gliadin when it’s found in the small intestine, causing inflammation that damages the body and leads to celiac symptoms.
How Many People Have Celiac Genes?
The HLA-DQ2 and HLA-DQ8 genes are present in 30% of the population, but only 3% of those with the genes develop celiac. It’s likely that other genes and environmental factors may also trigger disease development.
Which Tests Can Detect Celiac Disease?
If celiac is suspected, a helpful first step in the diagnostic process is to test for the presence of HLA-DQ2 and HLA-DQ8 genes.
The Vibrant Celiac Genetics test can help identify genetic predisposition for developing celiac disease by detecting mutations in the HLA-DQ2 and HLA-DQ8 genes to analyze the risk of developing celiac disease.
The Vibrant Wheat Zoomer tests for IgA and IgG antibodies at the peptide level to provide early and highly sensitive detection of celiac disease, as well as assessment of wheat sensitivity and intestinal permeability.
The test can identify patients with gluten-mediated autoimmunity based on their reactivity to transglutaminases; transglutaminase 2 (TG2) antibodies are specific to celiac disease.
Can Celiac Disease Be Traced Back to a Single Source?
Celiac disease is complex and can't be traced back to a single source.
However, knowledge is power—understanding the genetics behind the condition provides a helpful starting point for risk assessment and preventative treatment, as well as a better understanding of the disease as a whole.
Regulatory Statement:
The general wellness test intended uses relate to sustaining or offering general improvement to functions associated with a general state of health while making reference to diseases or conditions. This test has been laboratory developed and its performance characteristics determined by Vibrant America LLC and Vibrant Genomics, a CLIA-certified and CAP-accredited laboratory performing the test. The lab tests referenced have not been cleared or approved by the U.S. Food and Drug Administration (FDA). Although FDA does not currently clear or approve laboratory-developed tests in the U.S., certification of the laboratory is required under CLIA to ensure the quality and validity of the tests.
