The revolution of the genome-wide association study (GWAS) era has identified hundreds of genes associated with SpA, mainly IL23R, ERAP1 (Endoplasmic Reticulum Aminopeptidase-1), ERAP2, and MEFV (Mediterranean fever) linked to innate and acquired immune response and cytokines production (Brown et al., 2000). The gene discussed is ERAP1; the disease is brucellosis.