Five gene variants play important role in development coeliac disease

Five novel gene variants appear to play an important role in the development of coeliac disease, a common autoimmune disorder. These variants together account for 18% of the genetics of coeliac disease. This is the conclusion of a large-scale study led by geneticists Cisca Wijmenga from the UMCG and Paul de Bakker from the UMC Utrecht. This knowledge makes it possible to predict with increasing accuracy which patients are at risk of developing coeliac disease. In total, the researchers have now elucidated 48% of the genetic factors contributing to coeliac disease. The study has been published in the leading journal Nature Genetics of 20 April.

The genetic variants in question have been found in the HLA region. The genes in this region are known to play a crucial role in the immune system, in particular in distinguishing between ‘self’ and ‘non-self’ elements in the body. In coeliac patients, a particular HLA gene (HLA-DQ2) has been known for long to identify gluten as ‘non-self’.

People who do not have the HLA-DQ2 variant will never develop coeliac disease, but only 5% of those with the HLA-DQ2 variant will end up contracting coeliac disease. The fact that not every carrier of the HLA-DQ2 variant contracts the disease is important for research, as it can be used to develop new therapies and predict which patients are likely to develop coeliac disease.

Five newly identified variants

In their study, Wijmenga and De Bakker investigate whether variants other than the already known HLA-DQ2 variants also contribute to coeliac disease. To this end, they studied no less than 12,000 samples from 6 earlier studies on coeliac patients from 5 different countries.

The researchers were able to establish that five other variants contribute also contribute significantly to coeliac disease. Together, these five genetic variants explain 18% of the genetics of coeliac disease. In comparison HLA-DQ2 explains 23% of the genetics of coeliac disease and 40 genes scattered around the rest of the genome some 7%. The newly identified variants therefore greatly increase the available knowledge and the explained genetics.

There are at present 25,000 individuals in the Netherlands who have been diagnosed with coeliac disease. The actual number of people suffering from coeliac disease is probably much higher because the symptoms are not always immediately recognized.

Source: press release UMCG