Fig. 1.

Epigenetics and autoimmune disease. Five different epigenetic mechanisms have been identified so far: histone modification, non-coding RNA expression, DNA methylation, gene imprinting, and chromatin remodeling. These mechanisms interact with each other in a complex manner to regulate the expression and silencing of genes. Environmental factors may be the reason for the (high) discordance rate for autoimmune diseases in identical twins. These environmental factors may alter the epigenetic status quo and may trigger autoimmune diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), inflammatory bowel disease, as well as autoimmune diabetes, thyroid disease and hepatitis