There is clear evidence of a genetic component to coeliac disease. As well as the genetic component, coeliac disease only occurs if it is triggered. These factors lead to coeliac disease in 1 in 100 people, but many cases go undiagnosed.

Genes

A clear link exists between coeliac disease and certain tissue types, e.g. HLA DQ2. This means coeliac disease runs in families. HLA markers are found on white blood cells (an important part of the immune system) and have similarities to other markers found on red blood cells which are used to distinguish between blood groups. So far research has not identified a specific gene responsible for susceptibility to coeliac disease.

If coeliac disease exists in a family there’s about a one in ten chance for other members the family to develop coeliac disease. It’s important that all family members get tested even if they have no symptoms. It is possible to have coeliac disease without symptoms and it is damaging to your health if it goes undiagnosed and untreated. Other family members should not go on to a gluten-free diet without a proper diagnosis.

Triggers

Several types of event have been implicated with the onset of coeliac disease:

• viral infections
• introduction of gluten during weaning (too much or too early).

The scientific community does not yet fully understand the processes that lead to coeliac disease.

Prevalence

In the 1970s studies performed in Galway based on a positive biopsy result for coeliac disease showed the prevalence to be about 1 in 300 of the population of Co Galway, which was much higher than any other documented study.

It is felt that in most Caucasian populations the prevalence is nearer 1 in 100 although biopsy confirmation is lacking in many studies.

Many cases of coeliac disease go undiagnosed.