Genetic factors provide over 90% of the overall susceptibility to ankylosing spondylitis, with less than 50% of the genetic contribution attributed to HLA-B27 and other major histocompatibility complex genes. Therefore the researcher’s interest has focused on non-major histocompatibility complex genes. The regions implicated in susceptibility to ankylosing spondylitis have been confirmed on chromosomes: 1p, 2q, 3p, 6p (major histocompatibility complex region), 6q, 9q, 10q, 16q, 17p, 19q. Despite use of modern technologies only few non-major histocompatibility complex genes responsible for the susceptibility to ankylosing spondylitis were identified, most notably in the interleukin-1 gene complex.