The contribution of genes outside the major histocompatibility complex to susceptibility to ankylosing spondylitis

Purpose of review Recent data have presented several new nonmajor histocompatibility complex genes in predisposition to ankylosing spondylitis, which will be summarized here. Recent findings A retrospective meta-analysis of three previous whole genome linkage scans confirmed a strong linkage at chromosome 16q and moderate linkage at sites on chromosomes 3, 10, and 19q, and a meta-analysis of studies of the interleukin-11 (IL-1) region genes in ankylosing spondylitis suggested the susceptibility to be conferred by the IL-1 A gene. More recently, the use of genotyping chips, derived from the International Hapmap resource, which provides an extensive genomic coverage of large disease cohorts, have made it possible to conduct successful genome-wide association studies. One such study has led to the identification and validation of two new genes, IL23R and ARTS1, in ankylosing spondylitis pathogenesis. Summary A tremendous amount of progress has been made with respect to understanding the genetic basis of ankylosing spondylitis. The recent identification of two new genes, ARTS1 and IL23R, and confirmation of IL-1A association further substantiate that ankylosing spondylitis is determined to a large extent by genes outside the major histocompatibility complex.