A limited number of genes are behind the development of almost eleven immune-related diseases such as type 1 diabetes, coeliac disease, Crohn's disease and rheumatoid arthritis, according to new analysis.
Geneticists at the University Medical Center Groningen performed an analysis of all globally conducted association studies of these diseases.
According to the analysis although the diseases have different manifestations, they also have a major, comparable origin, reports Nature.
The revelation is a significant advance in the understanding of why patients can have several diseases at the same time, and why they occur more frequently within families.
In the analysis, the researchers investigated the joint genetic origins of various immune-related disorders. Almost 5 to 10 percent of the population have auto-immune and chronic inflammatory diseases such as type 1 diabetes, coeliac disease, Crohn's disease and rheumatoid arthritis.
Patients with these diseases often have problems with chronic infections and their immune systems often react against their own tissue. Such problems often lead to chronic infection reactions in, for example, the joints in the case of rheumatism and the large intestine in the case of Crohn's disease.
In fact, there have been cases where patients have more than one of these immune-related diseases, or that several family members are affected. Earlier studies have shown that heredity plays a role in the emergence of these diseases.
The researchers conducted genome-wide association study, analysing about 300,000 DNA variants to trace genes involved in the occurrence of diseases, for each individual. This technique has in recent years been used often for immune-related diseases and as a result many genes that play a role in these diseases have been identified.
Family studies had already revealed that there was possibly a joint hereditary basis underlying various immune-related diseases.
The scientists have conducted an extensive analysis of all the genome-wide association studies of these diseases that have been carried out anywhere in the world.
This led to a study of 11 immune-related diseases. It appears that 23 genes are involved in at least two immune-related diseases; each of these 23 genes is associated with at least two diseases.
Besides, further research revealed that the function of these genes overlaps. Many of these genes play a role in the development of the type of reaction by the immune system (Th1, Th2 or Th17) and which immune cells are activated as a result (T cells, B cells).
This indicated how the immune reaction is disturbed and that also provides possible reference frameworks for treatment (medication or perhaps vaccination).
The study is published in the latest edition of Nature Reviews Genetics.