PHTF1 and rheumatoid arthritis: Fourth, although a total of 27 ‘Asian-specific’ and 41 ‘European-specific’ newly identified genes are differentially expressed between RA patients and controls, only two ‘European-specific’ genes, PHTF1 and TNFRSF14, are validated by all the four functional studies, and, only PHTF1 shows an opposite RA/control ratios of mean expression value between Europeans and Asians.