The Second Multicenter Hemophilia Cohort Study (MHCS-II) will evaluate and prospectively follow approximately 4500 persons with hemophilia who were exposed to hepatitis C virus (HCV). The vast majority will have been infected with HCV, and approximately 1/3 will have been infected with human immunodeficiency virus (HIV). Primary objectives are to quantify the rates of liver decompensation, hepatocellular carcinoma, and non-Hodgkin lymphoma and to evaluate candidate clinical, genetic, virologic, serologic and immunologic markers that are likely to be on the causal pathway for these conditions. Candidate clinical and laboratory markers will be examined longitudinally to define changes over time and their relationships to one another. Collaborative studies will focus on genome scanning and evaluation of candidate genetic loci for susceptibility or resistance to HCV and HIV infections or to the diseases that result from these infections. Additional studies will identify response and complication rates of various anti-HCV and anti-HIV regimens in the setting of comprehensive clinical care of persons with hemophilia.

The Second Multicenter Hemophilia Cohort Study (MHCS-II) will evaluate and prospectively follow approximately 4500 persons with hemophilia who were exposed to hepatitis C virus (HCV). The vast majority will have been infected with HCV, and approximately 1/3 will have been infected with human immunodeficiency virus (HIV). Primary objectives are to quantify the rates of liver decompensation, hepatocellular carcinoma, and non-Hodgkin lymphoma and to evaluate candidate clinical, genetic, virologic, serologic and immunologic markers that are likely to be on the causal pathway for these conditions. Candidate clinical and laboratory markers will be examined longitudinally to define changes over time and their relationships to one another. Collaborative studies will focus on genome scanning and evaluation of candidate genetic loci for susceptibility or resistance to HCV and HIV infections or to the diseases that result from these infections. Additional studies will identify response and complication rates of various anti-HCV and anti-HIV regimens in the setting of comprehensive clinical care of persons with hemophilia.

• INCLUSION CRITERIA:

Must be registered patient with an inherited coagulation disorder at a participating MHCS-II center. Disorders include hemophilia A or B (congenital factor VIII or IX deficiency), deficiencies in other factors such as V or XI, and vonWillebrand's disease. (Unless noted otherwise, all of the disorders will collectively be referred to as hemophilia .) All such hemophilia and vonWillebrand s disease patients are to be recruited as study participants.

Since January 1, 1993, must have had at least one positive result on a licensed assay for HCV antibodies, HIV antibodies, or HIV RNA.

Must be at least 13 years of age at enrollment.

Must provide signed informed consent or, for minors, signed assent plus signed informed consent from the parent or guardian.

EXCLUSION CRITERIA:

Is not a patient with an inherited coagulation disorder.

Does not have a positive test for HCV antibodies, HIV antibodies, or HIV RNA on a licensed assay performed since January 1, 1993.

Is less than 13 years of age.

Lacks informed consent/assent.