Recent years witnessed a rapid improvement in the understanding of the genetic basis of AS, AAU and pediatric uveitis, including more than 69 subtypes of HLA-B27, as well as other immune-response genes, such as IL-1A, ERAP1, IL-23R in AS [18], TLR2, TLR4, TNF in AAU [19,20], and chemokine and chemokine-receptor genes in pediatric uveitis [21]. The gene discussed is ERAP1; the disease is uveitis.