Epigenetics and methylation in the rheumatic diseases.
OBJECTIVE
Rheumatic diseases encompass a wide range of conditions of poorly characterized etiopathology, many having both genetic and environmental susceptibility factors. Epigenetic studies are providing new insights into disease pathogenesis. Recent rheumatology literature related to DNA methylation studies-both epigenome-wide and candidate gene-are discussed, as well as methodological issues.


METHODS
A PubMed search for articles published until April 2013 was conducted using the following keywords: ("methylation" OR "epigenetics") AND ("rheumatoid arthritis" OR "lupus" OR "autoimmune disease" OR "osteoporosis" OR "osteoarthritis" OR "musculoskeletal disorder") and EWAS. The reference lists of identified articles were searched for further articles.


RESULTS
Several genome-wide methylation studies have been reported recently, mostly in autoimmune rheumatic diseases. Overall, these studies have identified methylation signatures in disease, clustering of subgroups as well as new and known epigenetic associations. Methodological issues, small sample sizes and reduced coverage of methylation assays render many results preliminary.


CONCLUSIONS
There have been a number of epigenetic advances in rheumatic diseases recently. The new technologies and emerging field of epigenome-wide association will provide novel perspectives in disease etiology, diagnosis, classification, and therapy.
Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom.
Flore
F
Zufferey
Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom.
Frances M K
FM
Williams
Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom. Electronic address: tim.spector@kcl.ac.uk.
Tim D
TD
Spector
D001327:Autoimmune Diseases / Q000235:genetics*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D006801:Humans; D012216:Rheumatic Diseases / Q000235:genetics*
Autoimmune diseases; EWAS; Epigenetics; Methylation; Rheumatic diseases