Congenital factor X deficiency

Congenital factor X deficiency, also known as Stuart-Prower factor deficiency, is a rare inherited bleeding disorder caused by a deficiency or dysfunction of coagulation factor X (FX). Factor X plays a central role in the blood clotting cascade, sitting at the convergence of both the intrinsic and extrinsic coagulation pathways. Because of this pivotal position, deficiency of factor X tends to produce a more severe bleeding phenotype compared to some other rare clotting factor deficiencies. The disease is caused by mutations in the F10 gene located on chromosome 13q34. It is inherited in an autosomal recessive manner, meaning that both copies of the gene must be affected for a person to manifest significant symptoms. Heterozygous carriers (with one affected copy) are usually asymptomatic or have only mild bleeding tendencies. The severity of symptoms generally correlates with the residual level of factor X activity. Patients with severe deficiency (factor X activity below 1%) may present in the neonatal period with life-threatening bleeding such as intracranial hemorrhage or umbilical cord bleeding. Those with moderate deficiency typically experience easy bruising, epistaxis (nosebleeds), menorrhagia (heavy menstrual bleeding), hemarthrosis (joint bleeding), gastrointestinal bleeding, and prolonged bleeding after surgery or trauma. Mucosal bleeding is common across all severity levels. Treatment of congenital factor X deficiency focuses on replacing the missing clotting factor. A high-purity, plasma-derived factor X concentrate (marketed as Coagadex) has been approved for on-demand treatment and perioperative management in patients with hereditary factor X deficiency. Fresh frozen plasma (FFP) and prothrombin complex concentrates (PCCs) may also be used when specific factor X concentrate is unavailable. Antifibrinolytic agents such as tranexamic acid can be helpful adjunctive therapy, particularly for mucosal bleeding. Prophylactic factor replacement may be considered in patients with severe disease and recurrent bleeding episodes. Genetic counseling is recommended for affected families.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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