Epigenetics and the microbiome: developing areas in the understanding of the aetiology of lupus

Reviews in this edition of Lupus bring together some of the most exciting research on the roles of environmental factors in the development of systemic lupus erythematosus. They explore the evidence behind some key exposures that have been associated with the risk of lupus. They also signal some real changes in the field, including an increasing focus on the mechanisms by which external factors may produce changes in the structure of DNA through the fast developing field of epigenetics. This area of research has become the ground upon which those with an interest in the effect of environmental factors on disease development are converging with geneticists. The overlapping edges between specialities are often fertile ground for discovery. Epigenetics describes the processes by which the likelihood of a protein being produced from its genetic code is altered by changes to the structure of the DNA and associated histones. These changes to structure influence the accessibility of the genetic code for the processes of transcription and translation. The structural changes include the addition of methyl groups to the DNA itself or the post-translational modification of histones around which the DNA is wrapped. Recent studies have shown the presence of altered levels of DNA methylation in lupus 1 and rheumatoid arthritis (RA). 2,3 Exposure