This is a single-center, decentralized, patient-centered, prospective, observational study utilizing biospecimen samples collected from hemophilia A subjects across the United States to evaluate and characterize seroprevalence and the rate of seroconversion of antibodies against AAV serotypes and exploratory vectors, and to investigate the associated factors that may influence the vector titers.~Relevant medical findings will also be collected from the subject, as well as symptoms related to hemophilia A. The collection of medical history may include major illnesses, diagnoses, and surgeries.
To quantify the seroprevalence of antibodies to AAV5, AAV6, and AAV8 and the seroconversion rate over varying follow-up intervals in subjects with hemophilia A