The idiopathic inflammatory myopathies (IIMs) represent a group of rare and heterogeneous 'orphan' autoimmune diseases characterized by inflammation of skeletal muscle and other organ systems, potentially leading to irreversible damage and resulting disability. The etiopathogenesis of IIM is likely to result from an interaction of genetic and environmental factors, which together are required to initiate the onset of a clinical disease phenotype It summarizes the previous and current literature on the immunogenetics of Idiopathic Inflammatory Myopathy (IIM) and updates the research progress that has been made over the past decade. A substantial part of the genetic risk for developing adult- and juvenile-onset IIM lies within the major histocompatibility complex (MHC), and a tight relationship exists between individual human leukocyte antigen alleles and specific serological subtypes, which in turn dictate clinical disease phenotypes.

 Multiple genetic regions outside of the MHC are increasingly being identified in conferring IIM disease susceptibility. We are still challenged with the task of studying a serologically and clinically heterogeneous disorder that is rarer by orders of magnitude than the likes of rheumatoid arthritis. An ongoing and internationally coordinated IIM genome-wide association study may provide further insights into IIM immunogenetics.

Regards

John
Editorial Assistant
Immunogenetics Open Access