Entering a new phase of immunogenetics in the idiopathic inflammatory myopathies.
OBJECTIVE
To review the progress that has been made in understanding the genetics of the idiopathic inflammatory myopathies (IIMs) in the past 2 years, with particular focus on polymyositis, dermatomyositis and inclusion body myositis.


RESULTS
Candidate gene studies in the Japanese population have implicated signal transducer and activator of transcription 4 as a risk locus for IIM, and HLA-DRB1 as a risk locus for anti-melanoma differentiation-associated gene 5-positive dermatomyositis. Evidence for gene-environment interactions has been found between HLA-DRB1*03 and smoking as a risk factor for the development of anti-histidyl tRNA synthetase antibodies, and HLA-DRB1*11:01 and statins for the development of anti-hydroxymethyl glutaryl-coenzyme A reductase-positive statin-induced myopathy. The HLA-DRB1*03:01/*01:01 genotype confers the highest disease risk in inclusion body myositis. A recent genome-wide association study has been performed in dermatomyositis. The most significant signals were in the major histocompatibility complex region, with other loci suggesting evidence of genetic overlap with different autoimmune diseases.


CONCLUSIONS
Recent association and gene-environment interaction studies have increased our knowledge of genetic risk factors for the IIMs. Ongoing international collaborations will facilitate larger and more meaningful genetic studies revealing much about the genetic architecture of these complex diseases.
aCentre for Musculoskeletal Research, Institute of Inflammation and Repair, The University of Manchester, Manchester bMRC/ARUK Institute of Ageing and Chronic Disease, Faculty of Health & Life Sciences, University of Liverpool, Liverpool cCentre for Integrated Genomic Medical Research, The University of Manchester, Manchester, UK.
Simon
S
Rothwell
Robert G
RG
Cooper
Janine A
JA
Lamb
Hector
H
Chinoy
D059647:Gene-Environment Interaction; D056726:Genetic Association Studies / Q000379:methods; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006681:HLA-D Antigens / Q000235:genetics; D006801:Humans; D009220:Myositis / Q000235:genetics* / Q000276:immunology; D012307:Risk Factors
D006681:HLA-D Antigens