It's not yet known why people develop coeliac disease. If you have coeliac disease, your immune system's response to gluten causes damage to the small intestine. The tiny, finger-like projections lining the bowel, called villi, become inflamed and flattened. This is called villous atrophy and it reduces the available surface area of the bowel to absorb nutrients from food. Some of the factors associated with an increased risk of developing this disease are outlined below. Family history Coeliac disease runs in families. If you have a parent or sibling with coeliac disease your risk of developing the condition is about 10 times higher than someone without a family history. Coeliac disease is strongly associated with the presence of certain genes called HLA DQ2 and HLA DQ8. Either one or both genes are present in almost every person with coeliac disease. These genes are very common in people in Australia. Around 56% of the population carries either one or both genes. This suggests there is a further trigger needed for coeliac disease to develop. Environmental factors Environmental factors may trigger coeliac disease at any age in people who carry the genes for the disease. Factors thought to play a role include: a previous gastrointestinal infection (such as a rotavirus infection), or a person’s diet during early childhood. Other health conditions Health conditions associated with an increased risk of developing coeliac disease include: type 1 diabetes ulcerative colitis neurological disorders such as epilepsy thyroid disease Down syndrome