While hydroxyurea (HU) is the initial drug of choice [16], [17] pegylated interferon-α (IFNα) is preferred in younger patients desiring offspring as HU is a potential teratogen [18, 19] and ruxolitinib, a JAK1/2 inhibitor for those PV patients who are intolerant or resistant to HU [20, 21]. This evidence concerns the gene IFNA1 and acquired polycythemia vera.