The cause of autoimmune diseases is point mutations
A "molecular switch" causing autoimmune diseases has been found
English geneticists have discovered mutations in DNA regions responsible for a number of genetic autoimmune diseases.
Autoimmune diseases are a number of different pathologies associated with the fact that the body begins to produce antibodies against its own healthy tissues and cells. Such diseases occur in 10% of the population of our planet. Diseases associated with inflammation of the mucous membrane of the digestive tract are especially common: ulcerative colitis, Crohn's disease and celiac disease.
English scientists in their new work drew attention to the genetic cause of such diseases. To do this, they applied genome-wide association search (GWAS) to the database of the National Institute for Human Genome Research. The essence of this method is to compare the genomes of sick and healthy people in order to find so-called single nucleotide polymorphisms, that is, point mutations in DNA regions that can be directly associated with autoimmune diseases.
"It is believed that these genetic variants contribute to the disease by altering the binding process of regulatory proteins and thus gene expression," the article says.
Scientists have discovered that in patients with ulcerative colitis, Crohn's disease and celiac disease, the DNA sections associated with the T-bet protein just have single nucleotide polymorphisms (snips).
In turn, T-bet is a transcription factor, that is, it regulates the production of immune T-lymphocytes. Because of the mutation, they begin to be produced more intensively, which contributes to the appearance of an autoimmune disease. At the same time, the scientists stressed that these mutations are not associated with autoimmune diseases such as rheumatoid arthritis or psoriasis.
It also turned out that a polymorphism called rs1465321 blocks the binding of T-bet to the IL18RAP gene. Thus, this gene is "disabled", which exposes its carrier to the risk of celiac disease.
Thus, for the first time, geneticists were able to discover that the transcription factor T-bet directly affects the occurrence of autoimmune diseases. This discovery opens up great prospects in their treatment.
The study was published in the journal PLoS Genetics (Soderquest et al., Genetic variants alter T-bet binding and gene expression in mucosal inflammatory disease).
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22.02.2017