Celiac Disease (Dubois, 2010) – Is celiac disease genetic?

Photo of gluten free salad bowl

Nebula Genomics DNA Report for Celiac Disease

Is celiac disease genetic? We created a DNA report based on a study that attempted to answer this question. Below you can see a SAMPLE DNA report. To get your personalized DNA report, purchase our Whole Genome Sequencing!

A sample report on celiac disease from Nebula Genomics
Sample variants on celiac disease from Nebula Genomics
To learn more about how Nebula Genomics reports genetic variants in the table above, check out the Nebula Research Library Tutorial.
This information has been updated to reflect recent scientific research as of July 2021.

What is Celiac Disease? (Part 1 of Is celiac disease genetic?)

Celiac disease, also known as gluten-sensitive enteropathy, is a long-term autoimmune condition caused by gluten intolerance that mainly affects the small intestine. It is not an allergy but a chronic inflammation of the mucosa of the small intestine due to hypersensitivity to components of gluten, a protein found in wheat, rye, and barley. Other organs may also be affected.

Foods containing gluten cause inflammation of the mucosa of the small intestine, often with extensive destruction of the intestinal epithelial cells. As a negative result, the intestine is damaged until it can no longer properly absorb nutrients. The symptoms and the severity of the clinical picture can vary greatly, making it difficult to recognize.

The digestive tract
Celiac disease affects the lining of the small intestine. Pixabay.

Possible symptoms include weight loss, diarrhea, vomiting, loss of appetite, fatigue, depression, bleeding tendency (due to vitamin K deficiency), and, in childhood, failure to thrive (slowed physical development). Neurological disorders may also occur.

Untreated celiac disease increases the risk of non-Hodgkin’s lymphoma (a blood cancer of the lymph nodes) and probably also of carcinomas of the digestive tract. In addition, celiac disease is associated with type 1 diabetes mellitus. 

There is no cure for celiac disease, but a gluten-free diet can help manage symptoms and heal the intestine. 

Did you know you can test for celiac disease at home? Learn more in this article about at home food sensitivities test!

Is Celiac Disease a Genetic Disorder?

People with certain variants of the HLA-DQA1 and HLA-DQB1 genes have a greater chance of developing celiac disease. These genes code for proteins that play a role in helping the immune system distinguish foreign invaders, such as bacteria and viruses, from the body’s own proteins. 

A “celiac genetic test” will search for human leukocyte antigens (HLA-DQ and HLA-DQ8), HLA genes associated with celiac disease susceptibility.   

When certain variants of these genes are present, the body creates an inappropriate response to a part of the gluten protein called the gliadin. Inflammation occurs as a result, leading to damage in the digestive tract and the ultimate symptoms of celiac disease. 

One important question that arises is: “is celiac disease hereditary?” Although, as explained above, there are genes that may increase the risk of developing the disease, no gene for celiac disease is inherited. However, the susceptibility of developing the disease may be passed on to the offspring. 

Almost all people with celiac disease have at least one of these genetic mutations. However, not all people with the mutations develop the condition. Specifically, about 30% of the general population has these mutations, but only 3% of people develop the disorder. This indicates that other factors, such as those in the environment, must be involved. 

Current Research on Celiac Disease [Updated July 2021]

Discoveries on characteristics and causes of celiac disease, as well as treatments, constantly take place. This is thanks to the interest of scientists in the factors affecting the development of the condition. A group of researchers from several US universities has been updating this study for over a decade. Its last update was on January 31, 2019.

A 2017 study revealed that a viral infection caused by reovirus could trigger the development of celiac disease. This other research, published the same year, involving reovirus infection, seems to confirm that the virus does trigger food sensitivity and celiac disease. 

Scientists have found a challenge in determining the best course of action for the treatment of CD, except “strict adherence to a gluten-free diet (GFD),” as expressed in this 2019 paper. You can also take a look at this 2019 review of how CD is a challenging condition due to an increase in knowledge through the years. 

However, more recent discoveries and trials bring in hopes for treatment on the disease. For example, a group of health care providers published their results on random trials of transglutaminase 2 inhibitor to treat the condition in The New England Journal of Medicine only this month. 

To get the most relevant information and news about current research on CD, the Celiac Disease Foundation specializes in collecting results and impressions. 

Epidemiology (Part 4 of Is celiac disease genetic?)

This condition is relatively common, especially in the United States and Europe. Most celiac disease statistics and estimates believe the prevalence to be around 1.4% in the US and 0.7% in Europe, making the overall average as 1 in 100 people having the condition. The prevalence of celiac disease has been increasing in recent years, which most scientists believe is related to better recognition and diagnostic techniques. Recent data has shown that the condition is also present in other areas of the world, including South America, the Middle East, Turkey, and sub-Saharan Africa. However, celiac disease diagnosis numbers are still low in those places. 

It affects females slightly more than males, with women making up about two-thirds of those diagnoses. There is a 17.4 per 100,000 person-years incidence in women against a 7.8 per 100,000 person-year among men. The condition can occur at any age at which gluten is introduced into the diet, but symptoms typically start around age 6 or 7. It is most commonly diagnosed around the age of 40 in the United States.

Symptoms (Part 5 of Is celiac disease genetic?)

The presentation of celiac disease is difficult to define because there can be hundreds of celiac disease symptoms affecting different parts of the body, and the condition affects each patient differently. There is no standard of age of onset, occurring in both children and adults with different symptoms depending on age. And sometimes, there may be no symptoms at all even though those patients are still at risk for long-term complications.

Children

Children with celiac disease most often have digestive problems. The most common symptoms in children defined by the Celiac Disease Foundation include:

  • chronic diarrhea
  • abdominal bloating and pain
  • vomiting
  • constipation
  • pale, foul-smelling, or fatty stool

The digestive symptoms often result in poor absorption of nutrients which causes additional conditions including:

Inflammation caused by celiac disease
Inflammation of the intestinal mucosa may lead to villous atrophy of the small intestine. Wikipedia. CC-Attribution-Share Alike 4.0 International.  

Adults

When the condition presents itself in adults, it usually does not show as many signs of digestive issues. Adults are more likely to experience:

  • unexplained iron-deficiency anemia
  • fatigue
  • bone or joint pain
  • arthritis
  • osteoporosis or osteopenia (bone loss)
  • liver and biliary tract disorders 
  • depression or anxiety
  • peripheral neuropathy (tingling, numbness, or pain in the hands and feet)
  • seizures or migraines
  • missed menstrual periods
  • infertility or recurrent miscarriage
  • canker sores inside the mouth
  • dermatitis herpetiformis (itchy skin rash)

Some patients have what is known as silent celiac disease, where the condition does not show any identifiable symptoms. However, the immune response still occurs, and intestinal damage can be observed through a biopsy.

Causes (Part 6 of Is celiac disease genetic?)

Celiac disease is caused when persons with certain genetic compositions consume gluten, which causes an immune reaction in the small intestine.

Since not every child with a genetic predisposition develops the condition, scientists are investigating other environmental factors that may affect its presentation. The National Institute of Diabetes and Digestive and Kidney Diseases notes that a higher number of infections early in life and certain infections in the digestive tract probably increase risk factors. Changes in the microbiome, the community of bacteria in the digestive tract, may also play a role. 

Did you know you can check your microbiome health at home? Check out reviews of these at-home microbiome tests:

  • Biohm (gut health, including bacteria and fungi) 
  • DayTwo (gut health, personalized recommendations for blood glucose optimization)
  • Onegevity (gut health and personalized recommendations)
  • Psomagen (gut health and gene test)
  • Thryve (personalized probiotics)
  • Viome (gut health and microbiome testing)

As of now, children who are at higher risk due to genetics and eat a higher amount of gluten in childhood are most at risk.

Diagnosis of Celiac Disease (Part 7 of Is celiac disease genetic?)

The condition often goes undiagnosed due to the range of non-specific symptoms. That is, most signs are common in many other illnesses, and most people with two or more of hallmark symptoms do not have celiac disease. In many cases, patients are not diagnosed until ten years or more after the condition begins. 

In addition to family history and physical examination for symptoms, your doctor will diagnose your condition by testing in the forms of blood tests, biopsies, or genetic screening to rule out celiac disease. 

Since the condition runs in families, first degree family members of celiac disease patients should get tested, either through blood tests or genetic screening, as they have an increased risk of developing the condition.

Blood tests

When the immune system reacts to gluten, it produces a higher than average amount of certain antibodies. Blood tests can detect these antibodies. However, it is important to follow instructions carefully to ensure this test is accurate. Generally, antibody testing may not be accurate in children under the age of 2 or 3, and thus these children should only be tested if symptoms are present. 

In most cases, children must eat a gluten-containing diet for at least a year before enough antibodies build up in the body to be detectable in a blood test. This is why this testing does not work well for those under two years of age. 

Foods that can aggravate celiac disease
A gluten containing diet will consist of products like bread and anything that contains wheat. Pxfuel.

The most common antibody combination tested for is the Tissue Transglutaminase IgA antibody, plus an IgA antibody. This test will be positive in 98% of patients with the condition on a gluten-containing diet. It is the most sensitive antibody test available. Some people with associated autoimmune diseases like type 1 diabetes, autoimmune liver disease, Hashimoto’s thyroiditis, psoriatic or rheumatoid arthritis, and heart failure may have a false positive test. In these cases, other conditions may be ruled out with other antibody tests. However, the only way to positively diagnose celiac disease is through a biopsy of the small intestine. 

Genetic testing

Your doctor may recommend a blood test or commercial genetic test to screen for the genes for celiac disease, HLA DQ2, or HLA DQ8. Almost all patients have certain variations of these genes. However, so does 30% of the general population. The presence of DQ2 and DQ8 variants does not mean you will develop the condition. Instead, it increases your risk of developing celiac disease from 1% to 3%. 

Since it is a genetic condition, first-degree relatives like parents and siblings are at an increased risk of carrying the genes and developing the disease. 

People without these variants are unlikely to have the condition. Even if they don’t show symptoms, first degree relatives may want to consider genetic testing as the test results can rule out the presence of the genetic variants that may lead to the condition later in life or suggest a silent form.

Biopsies

A small intestine biopsy is the only definite way to diagnose celiac disease. Biopsies are obtained through an upper GI endoscopy. In this process, a small, flexible tube with a camera is passed through the upper GI tract, including the first part of the small intestine. First, an instrument collects small pieces of tissue. Then, the tissue is observed for hallmark signs of the condition under a microscope by a trained pathologist. 

Damage from celiac disease
A biopsy of celiac disease. Wikipedia. CC-Attribution-Share Alike 3.0 Unported.

Treatment (Part 8 of Is celiac disease genetic?)

The only way to manage celiac disease is to adhere to a strict gluten-free diet. This includes refraining from eating foods like wheat, barley, rye, and products that contain gluten. There are special dieticians who treat patients with celiac disease who can recommend the proper gluten free foods and diets. Even small amounts of gluten that do not cause noticeable symptoms have the potential to damage the small intestine. 

A person suffering from celiac disease must avoid any food containing gluten. You should only start new diet plans on the advice of your physician. 

In addition to foods, gluten may be present in medications and non-food products. Mayo Clinic lists some of these problem areas:

  • Modified food starch, preservatives, and food stabilizers
  • Prescription and over-the-counter medications
  • Vitamin and mineral supplements
  • Herbal and nutritional supplements
  • Lipstick products
  • Toothpaste and mouthwash
  • Communion wafers
  • Envelope and stamp glue
  • Playdough

Gluten-free products contain special labeling on their package. To substitute foods with gluten, those with celiac disease eat grains such as buckwheat, corn, flax, soy, chickpea, lentil, millet, potato, pure oats, and quinoa.

A gluten free label
Gluten free products will be marked on the packaging. Pixabay.

For most patients, a gluten-free diet will allow the intestine to heal, and symptoms will dissipate. For children, healing can be as quick as three to six months, whereas it could take up to several years for adults. An endoscope with biopsies can be used to determine if the intestine has healed. 

This article is for educational purposes only. You should seek professional medical advice if you think you may have this condition or are thinking about drastically changing your diet. 

Important note: This website is not intended to diagnose any disease and this information on gluten is not a substitute for professional medical advice. You can also learn more at a Celiac Disease Center near you.

If you liked this article, you should check out our other posts in the Nebula Research Library!