Ann Rheum Dis 64:ii37-ii39 doi:10.1136/ard.2004.030775
  • Psoriatic arthritis and psoriasis: classification, clinical features, pathophysiology, immunology, genetics

Genetic epidemiology of psoriasis and psoriatic arthritis

  1. P Rahman1,
  2. J T Elder2
  1. 1St Clare’s Mercy Hospital, Memorial University of Newfoundland, St John’s, Newfoundland, Canada
  2. 2Departments of Dermatology and Radiation Oncology, University of Michigan, Ann Arbor, MI; and Ann Arbor Veterans Affairs Health System, Ann Arbor, MI, USA
  1. Correspondence to:
    Dr P Rahman
    St Clare’s Mercy Hospital, 1 South, 154 LeMarchant Rd, St John’s, Newfoundland, Canada A1C–5B8;


    Psoriasis and psoriatic arthritis (PsA) are interrelated disorders, as most patients with PsA also have psoriasis. Thus it is not surprising that epidemiological and immunogenetic studies have uncovered important links between these two disorders. Both disorders are highly heritable, and the prevalence of psoriasis is 19 times higher among first degree relatives of probands with PsA compared with the general population. Multiple human leucocyte antigen (HLA) associations are shared between psoriasis and PsA, though the magnitudes of these associations differ between the diseases. Genome-wide linkage studies have noted overlapping regions of significance for these two disorders within and outside the major histocompatibility complex (MHC) region. Thus, exploration of the genetic basis of psoriasis will likely strengthen the contention of an underlying genetic susceptibility for PsA and vice versa.


    • JTE acknowledges support from the National Institute of Arthritis, Musculoskeletal, and Skin Diseases, the National Psoriasis Foundation, the Babcock Memorial Trust, and the Ann Arbor Veterans Affairs Health System.

    • PR is a CIHR New Investigator and Arthritis Society Scholar