ABO and Venous thrombosis: Among the rest fifteen SNPs detected, the rs495828 of ABO gene was significant relevant to an increased risk of thrombosis in PNH patients, as shown by the dominant model (GT+TT vs. GG: OR 5.95, 95% CI 1.90-18.65, P=0.002) and allele model (T vs. G: OR 3.52, 95%CI 1.57-7.90, P=0.003).