title: New developments in genetics of myositis.
abstract: OBJECTIVE
  This article reviews the advances that have been made in our understanding of the genetics of the idiopathic inflammatory myopathies (IIM) in the past 2 years, with a particular focus on polymyositis, dermatomyositis and inclusion body myositis.
  
  
  RESULTS
  Two large human leukocyte antigen (HLA) imputation studies have confirmed a strong association with the 8.1 ancestral haplotype in clinical subgroups of myositis and suggest multiple independent associations on this haplotype. Risk in these genes may be due to specific amino acid positions within the peptide-binding grooves of HLA molecules. A large genetic study in 2566 IIM patients revealed associations such as PTPN22, STAT4, UBE2L3 and BLK, which overlap with risk variants reported in other seropositive autoimmune diseases. There is also evidence of different genetic architectures in clinical subgroups of IIM. Candidate gene studies in the Japanese and Chinese populations have replicated previous IIM associations which suggest common aetiology between ethnicities.
  
  
  CONCLUSIONS
  International collaborations have facilitated large genetic studies in IIM that have revealed much about the genetics of this rare complex disease both within the HLA region and genome-wide. Future approaches, such as sequencing and trans-ethnic meta-analyses, will advance our knowledge of IIM genetics.
authors.affiliation: aCentre for Musculoskeletal Research, University of Manchester, Manchester, UK bCentre for Integrated Genomic Medical Research, University of Manchester, Manchester, UK cCentre for Musculoskeletal Research and National Institute of Health Research, Manchester Musculoskeletal Biomedical Research Unit, Central Manchester University Hospitals NHS Foundation Trust, University of Manchester, Manchester, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Rothwell
authors.forename: Janine A
authors.initials: JA
authors.lastname: Lamb
authors.forename: Hector
authors.initials: H
authors.lastname: Chinoy
mesh_terms: D001327:Autoimmune Diseases / Q000235:genetics; D003882:Dermatomyositis / Q000235:genetics / Q000276:immunology; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006680:HLA Antigens / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D009220:Myositis / Q000235:genetics* / Q000276:immunology; D018979:Myositis, Inclusion Body / Q000235:genetics / Q000276:immunology; D017285:Polymyositis / Q000235:genetics / Q000276:immunology; D012307:Risk Factors
chemical_list: D006680:HLA Antigens