COL4A2 and platelet-type von Willebrand disease: We collected data on: hemostatic genes (factor V deficiency, von Willebrand’s disease, factor VII deficiency), protrombothic genes (factor V Leiden, MTHFR mutation, protein C deficiency), collagen genes (COL4A1 and COL4A2 mutations), and X linked GATA1 gene mutation.