Coeliac Disease (Gluten-Sensitive Enteropathy, Coeliac Sprue)

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What is Coeliac Disease?

Coeliac disease is a chronic inflammatory disease of the small bowel. In genetically susceptible individuals, ingestion of gluten (a protein found in wheat, barley and rye) causes injury to the lining of the small bowel, resulting in diarrhoea and malabsorption of nutrients and minerals. It usually affects the first part of the small bowel (duodenum and jejunum), but can affect the entire small bowel in some people.

Who gets Coeliac Disease?

Coeliac disease is a common condition which affects 1% of people in Western populations. It is more common among Caucasians but less common among people of African and Asian descent. In Australia, it occurs in at least 1 in 250 people. Symptoms may start at any age, ranging from infancy to adulthood. For unknown reasons, it is 2-3 times more common in women than men.

Predisposing Factors

Environmental factors

It is clear that coeliac disease is associated with the ingestion of gliadin, which is a component of gluten. Gluten is present in wheat, rye, barley and, in smaller amounts, oats. A gluten free diet reverses both patient symptoms and damage to the small bowel. Exposure to other environmental antigens (e.g. a virus) may also have a role in triggering the onset of the disease. Other risk factors may include breastfeeding, when gluten ingestion commences, and smoking.

Immunological factors

People with coeliac disease have certain antibodies in the blood, such as IgA antigliadin, IgA antiendomysial, and IgA anti-tissue transglutaminase (tTG) antibodies. These antibodies are rarely seen in people without coeliac disease, but it is unknown whether these antibodies actually cause coeliac disease or are a result of the disease.

Genetic factors

Coeliac disease has a genetic component: 10% of immediate family members are likely to have the disease as well, even though they may experience no symptoms.

Almost all people with coeliac disease have certain genetic components (alleles) known as HLA-DQ2 or HLA-DQ8. However, these two alleles are also present in around 30% of the population, and most of those people do not have coeliac disease. Therefore, there may be other genes or factors that are also involved in causing coeliac disease.

Associated diseases

Coeliac disease is associated with other autoimmune diseases, including diabetes mellitus type 1, IgA deficiency, thyroid disease, primary biliary cirrhosis, Sjogren's syndrome, and a skin condition known as dermatitis herpetiformis.

Progression

The first symptoms of coeliac disease may appear in infancy after the introduction of cereals in the diet. Children may grow out of it during adolescence, but some experience a return of symptoms a few years later. Alternatively, the symptoms may first appear at any age from infancy through to adulthood. Many patients experience frequent attacks of disease that come and go spontaneously. Different people experience different symptoms, ranging from mild/minimal to severe, but the majority get relief after starting a gluten-free diet.