Our study demonstrates that some genotypes and haplotypes in PADI2 and PADI4 are related to disease severity and death [TT in PADI2, GTG and ACC in PADI4]. The frequency of PADI2 haplotype was identical to the reported in RA and healthy populations from Mexico [32], and the frequency of PADI4 haplotypes was similar to the reported in populations from Japan [22], Korea [35], China [23] and, Ukraine [33]. Here, PADI4 is linked to rheumatoid arthritis.