IL23R and ankylosing spondylitis: An important series of evidences originates from genetic studies: Genome-Wide Association Studies (GWAS; International Genetics of Ankylosing Spondylitis Consortium (IGAS) et al., 2013) have convincingly established the association between AS and genetic variants in loci involved in the Th17 pathway, including TYK2, IL6R, IL1R1, IL1R2 and IL23R, whose products are important for the induction and survival of the Th17 response.