Based on earlier reports in RA, psoriasis and psoriatic arthritis [18], [23], [24], [25] and linkage disequilibrium patterns in Han Chinese, in combination with Japanese data in the Hap Map database, we selected three SNPs (rs6540679 Chr.1: 211491152, rs12569232 Chr.1: 211553064, rs10863888 Chr.1: 211502769) of TRAF5 and three SNPs (rs13210247 Chr.6: 111922720, rs33980500 Chr.6: 111913262, rs13190932 Chr.6: 111913070) of TRAF3IP2 as candidate SNPs for our study (Figure 1). The gene discussed is TRAF5; the disease is psoriatic arthritis.