Progression of thrombocytopenia tended to be worse in patients carrying the CA/AA allele, as reported previously, but there was no significant difference in platelet count at 4, 8 and 12 weeks after initiation of PEG-IFN/RBV (69.9 × 103/μl vs 63.2 × 103/μl; P = 0.26, 71.5 × 103/μl vs 61.3 × 103/μl; P = 0.23, 69.5 × 103/μl vs 66.2 × 103/μl, P = 0.28, respectively, Figure 3A). Here, IFNA1 is linked to Thrombocytopenia.