dDAVP was initially developed for the treatment of nephrogenic diabetes insipidus (NDI); then, due to its ability to increase plasma levels of FVIII [6] and the von Willebrand factor (vWF), its use was extended to patients with bleeding disorders, such as mild and moderate hemophilia A, selected types of von Willebrand Disease, several forms of platelet dysfunction, and uremic bleeding [7]. The gene discussed is VWF; the disease is Von Willebrand disease.