However, alluded to in the following discussion, GWAS studies have shown that the IL-23 pathway related genetic polymorphisms occur along the entire SpA arthropathy spectrum including ankylosing spondylitis and psoriatic arthritis, in psoriasis and inflammatory bowel disease and indeed in BD, thus completely vindicating the entire concept alluded to by Moll and Wright (9, 10). Here, IL23A is linked to psoriatic arthritis.