X-linked thrombophilia due to factor IX defect

A thrombophilia characterized by normal levels of F9 antigen, but very high levels of F9 activity that has_material_basis_in hemizygous gain of function mutation in F9 on chromosome Xq27.1.

Signs and symptoms

• Increased factor IX activity
• Deep venous thrombosis
• Hypercoagulability

Also known as: THPH8