- In utero gene transfer of human factor IX to fetal mice can induce postnatal tolerance of the exogenous clotting factor. Waddington, S.N., Buckley, S.M., Nivsarkar, M., Jezzard, S., Schneider, H., Dahse, T., Kemball-Cook, G., Miah, M., Tucker, N., Dallman, M.J., Themis, M., Coutelle, C. Blood (2003)