Phenotypic Heterogeneity in Hemophilia A: An Investigation of the Role of Platelet Function

Phenotypic Heterogeneity in Hemophilia A: An Investigation of the Role of Platelet Function

The is study will examine whether variation in clinical bleeding frequency and severity among boys with severe Hemophilia A (Factor VIII deficiency) is associated with variations in laboratory measurements of platelet activity.

Inclusion Criteria:

• documented circulating FVIII level of ≤1%
• age 3 - 20 years
• may be on primary or secondary prophylaxis
• granting of informed consent

Exclusion Criteria:

• measurable inhibitor level at the time of enrollment
• ingestion of aspirin/supplement known to influence platelet function within 14 days of blood sampling, or ibuprofen within 3 days