How Are Your Genes and Environment Linked in RA Development?

There is now evidence that whether or not your wellness is affected by the development of rheumatoid arthritis (RA) depends on how epigenetic changes to your DNA mediate the influence of environmental factors. This is according to research published recently in Nature Biotechnology.

RA is already known to be influenced by both genetic and environmental factors, like most common diseases are, and scientists have previously linked RA to the regions of your genome that are associated with the immune system. This is hardly surprising, because RA is an autoimmune disease, meaning that components of your immune system attack your body’s own tissues. It terms of specific environmental risks, RA has been linked to smoking.

It is also known that epigenetic changes link environment and gene expression generally. The environmental factors alter the genome’s methylation, which in turn changes how genes are express, but until now scientists have no been able to demonstrate a robust association between epigenetic modifications and common disease, at least not using genome-wide association studies (GWAS).

For this study, the researchers identified two clustered regions of the genome where differences in methylation were associated with risk of the disease, using DNA samples from 354 individuals with rheumatoid arthritis and 337 controls without the disease. The results were that the methylation changes will only occur in these regions if you have particular gene variants. This led the researchers to conclude that the methylation changes themselves were the likely mediators of environmental exposures on genetic risk.

This study is important because it provides some of the first direct evidence of specific epigenetic changes mediating risk of a specific human disease. Not only does this contribute to the model we are forming of the mechanisms that your genes use to influence your risk of disease, but it could also ultimately help us to better understand exactly why you may be more susceptible to environmental risk factors than someone else.