Characterization of Laboratory Response to DDAVP in Adult Hemophilia A Carriers

Inclusion Criteria: Inclusion criteria for hemophilia A carriers: * Females 18-60 years of age at time of enrollment * Genetically verified or obligate hemophilia A carrier (mother of 2 boys with hemophilia A, daughter of a father with hemophilia A or mother of a son and another male relative with hemophilia A) * To stratify patients by carriage of mutation type 10 hemophilia carriers of mild mutations that are predicted to lead to reduced FVIII secretion, protein stability or thrombin cleavage site interference and 10 hemophilia carriers of severe mutations that lead to predicted negative cross reactive material will be selected. Predicted FVIII function of the mutation will be verified by EAHAD (European Association for Haemophilia and Allied Disorders) Coagulant Factor Variant Database at www.eahad-db.org) * Weight \>40kg to ensure volumes of blood to be drawn are within accepted safe range Inclusion criteria for non-hemophilia A carriers (Females with mild qualitative platelet dysfunction): * Females 18-60 years of age at time of enrollment * Whole blood or platelet rich plasma lumiaggregometry consistent with reduced aggregation to at least 1 agonist on at least one occasion (excluding evidence of Glanzmanns Thrombasthenia or Bernard Soulier Syndrome) or determined by primary hematologist as having a qualitative platelet disorder * Age-matched by 10 years to carrier enrolled * Weight \>40kg to ensure volumes of blood to be drawn are within accepted safe range Exclusion Criteria: * Personal history of concomitant bleeding or clotting disorder * Cardiac condition that requires the daily use of Aspirin or Clopidogrel * Inability to comply with fluid restriction protocol for 24 hours following Desmopressin (DDAVP) * Personal history of a myocardial infarction, renal or hepatic insufficiency or epilepsy