Rare Factor Deficiencies
Rare Factor Deficiencies
Factor VII is the most prevalent of the rare deficiencies. The North American Rare Bleeding Disorders Registry (NARBDR) has documented that FVII deficient patients represent 46% of reported rare bleeding disorder patients (excluding FXI deficiency). 35% of FVII deficient patients have documented FVII levels of <20% activity level.
Although specific replacement products have been licensed for this disorder in much of the rest of the developed world, no replacement product is currently licensed to treat factor VII deficiency in the US. Recombinant factor VIIa is licensed to treat patients with inhibitors to factor VIII and IX. Multiple reports exist in the literature regarding the use of rFVIIa for treatment of factor VII deficiency.
How Many People Have Rare Factor Deficiencies?
Blood clotting is a complex process, involving many different proteins, called factors, each of which plays a different role in the blood clotting process. Factor deficiencies are defined by which specific clotting protein in the blood protein is low, missing or doesn’t work properly.
- Factor I (1) Deficiency is a collective term for three rare inherited fibrinogen deficiencies. One of these, afibrinogenemia is very rare, occurring in 1-2 people per million.
- Factor II (2) Deficiency is estimated to occur in 1 out of every 2 million people.
- Factor V (5) Deficiency is estimated to occur in 1 out of every 2 million people.
- Factor VII (7) Deficiency is estimated to occur in 1 out of every 300,000-500,000 people. That makes it the most common of the rare factor deficiencies.
- Factor X (10) Deficiency is estimated to occur in 1 in 500,000 to 1 in a million people.
- Factor XI (11) Deficiency (Hemophilia C) is estimated to occur in 1 in 100,000 people.
- Factor XII (12) Deficiency is estimated to occur in 1 in a million people.
- Factor XIII (13) Deficiency is estimated to occur in 1 in 5 million people. It is the rarest of the rare factor deficiencies.