PADI4 and rheumatoid arthritis: In addition, our results agree with the pioneering study of PADI4 polymorphisms by Suzuki et al. in a Japanese population [8], in which they reported that the GTG haplotype is associated with RA risk, more stable mRNA (half-lives of 11.6 in GTG carriers vs. 2.1 min in ACC carriers), an higher levels of PAD4 protein than the ACC carriers [8].