What is Coeliac Disease

Coeliac disease (pronounced seel-ee-ak) is a an auto-immune disease. Auto-immune means the body mistakenly produces antibodies that damage its own tissues. It is a permanent intestinal intolerance to dietary gluten. A number of serious health consequences can result if the condition is not diagnosed and treated properly.

In those with untreated coeliac disease the mucosa (lining) of the small bowel (intestine) is damaged: The tiny, finger-like projections which line the bowel (villi) become inflamed and flattened. The function of the cells on villi is to break down and absorb nutrients in food. Through a microscope, the lining of the small bowel normally looks rather like shag-pile carpet, the villi making up the “pile”. The entire surface area of a healthy small bowel is comparable in size to that of a tennis court.

In those with untreated coeliac disease, the villi become inflamed and the bowel has a characteristic flat appearance (like a threadbare carpet). This is referred to as villous atrophy. The surface area of the bowel available for nutrient absorption is markedly reduced (to the size of a table or less) which can lead to nutrient deficiencies.

What is the Cause?

In people with coeliac disease the immune system reacts abnormally to gluten, causing small bowel inflammation and damage. Gluten is a protein found in wheat, rye, barley and oats.

Who gets Coeliac Disease?

People are born with a genetic predisposition to develop coeliac disease. They inherit a particular genetic make-up (HLA type) with the genes DQ2 and DQ8 being identified as the “coeliac genes”. Gene testing is presently available through pathology laboratories (by blood test or buccal swab). The gene test is useful for excluding coeliac disease. The presence of HLA DQ2 and HLA DQ8 is not helpful as a positive predictor of coeliac disease, as only 1 in 30 people (approximately) with these genes will have coeliac disease. The gene test cannot diagnose coeliac disease – only exclude it.

Environmental factors also play an important role in the development of coeliac disease.

A first-degree relative (parent, brother, sister, child) of someone with coeliac disease has about a 10% chance of also having the disease. If one identical twin has coeliac disease, there is an approximate 70% chance that the other twin will also be affected (but not necessarily diagnosed at the same time). This highlights the role of both genetic and environmental factors in the development of coeliac disease.

Coeliac disease affects Caucasians and west Asians. It is uncommon in the Oriental Asian and full-blood Australian Aboriginal populations.

Coeliac disease can also be associated with other autoimmune conditions such as type 1 diabetes, autoimmune thyroid disease, pernicious anaemia, rheumatoid arthritis, inflammatory bowel disease and lupus. It has not been shown that there is a causative link, but having one genetic autoimmune disease increases your risk of having another.

How Common is the Condition?

Coeliac disease affects approximately 1 in 100 Australians. However 80% currently remain undiagnosed. This means that approximately 200,000 Australians have coeliac disease but don’t yet know it.

Can Coeliac Disease be cured?

People with coeliac disease remain sensitive to gluten throughout their life, so in this sense they are never cured. There is no correlation between symptoms and bowel damage, so even if asymptomatic (you have no symptoms), damage to the small bowel can still occur if gluten is ingested. Once gluten is removed from the diet, the small bowel lining steadily repairs and the absorption of nutrients from food returns to normal.

People with coeliac disease should remain otherwise healthy as long as they adhere to a diet free of gluten. Relapse occurs if gluten is reintroduced.

How is the Condition Recognised?

The underlying genetic predisposition to develop coeliac disease is present at birth. Coeliac disease was once considered to be a childhood condition, which only produced symptoms in very young children. It is now recognised that coeliac disease may be triggered at any time from infancy to senior years. Some infants become rapidly and severely ill when foods containing gluten are introduced into their diet; other children develop problems slowly over several years. Many have few or no problems during childhood but develop symptoms only as adults. In addition, the symptoms of coeliac disease can range from severe to minor or atypical and can even be clinically silent. Some symptoms may be confused with irritable bowel syndrome or a food intolerance, while others may be put down to stress, or getting older. As a consequence it may take some time before an accurate diagnosis is sought, or made.

What are the Long Term Risks of Undiagnosed Coeliac Disease?

The long term consequences of coeliac disease are related to poor nutrition and malabsorption of nutrients. Untreated coeliac disease can lead to chronic poor health, osteoporosis, infertility, miscarriage, depression and dental enamel defects. There is also a small, but real, increased risk of certain forms of cancer such as lymphoma of the small bowel. In children, undiagnosed coeliac disease can cause lack of proper development, short stature and behavioral problems.