It has been reported that the clinical phenotype may improve with age, depending on mutation, and therefore some patients with severe HA may present with a mild bleeding phenotype.7 In the literature, variation in clinical phenotype has been attributed to co-inheritance of inherited thrombophilia such as deficiencies in protein C, protein S, antithrombin and factor V Leiden mutation.7 The gene discussed is PROS1; the disease is Rare hereditary thrombophilia.