Previous reports showed that platelet-restricted expression of FVIII using megakaryocyte-specific promoters (glycoprotein (Gp) αIIb [31, 33, 34], Gp1bα [35] and platelet factor 4 [36]) can partially correct hemophilia phenotype in transgenic mice or in lethally irradiated HemA mice treated with ex vivo gene therapy. Here, F8 is linked to hemophilia.