However, this theory was challenged by analysis of ERAP1 SNP haplotypes from a larger cohort of AS patients and RA controls, which argues that ERAP1 allele combinations in AS patients reported by Reeves et al. are pretty rare, and that most ERAP1 allele combinations from AS patients are shared with RA controls and do not necessarily contain one hyperactive allotype or two hypoactive allotypes (96). This evidence concerns the gene ERAP1 and rheumatoid arthritis.