Congenital Factor X Deficiency

A rare inherited bleeding disorder with a decreased antigen and/or activity of factor X (FX) and characterized by mild to severe bleeding symptoms.

Epidemiology

Prevalence of homozygous forms is estimated at 1/1 000 000. Both sexes are equally affected.

Clinical description

Congenital FX deficiency manifests at any age but in general, severe forms of the disease manifest early in life. Patients may experience severe umbilical cord stump bleeding, recurrent epistaxis, soft-tissue hemorrhages, menorrhagia, easy bruising, intra cranial hemorrhages, hematuria, hemarthroses and excessive bleeding during or following surgery or delivery or trauma.

Etiology

Inherited congenital FX deficiency is caused by mutations in the F10 gene (13q34) controlling the production of plasma FX. The severity of the bleeding manifestations correlates with the FX level.

Diagnostic methods

Diagnosis is based on prolonged prothrombin, activated partial thromboplastin, and Russell viper venom times (PT, aPTT, RVVT), and on reduced levels of FX. Molecular testing is available, but unnecessary for diagnosis.

Differential diagnosis

Differential diagnoses include deficiencies of factors II, V, VII, VIII, IX, XI, XIII or acquired deficiencies in FX (amyloidosis).

Genetic counseling

Transmission is autosomal recessive. Genetic counseling should be offered to at-risk couples (both individuals are carriers of a disease-causing mutation) informing them of the 25% risk of having an affected child at each pregnancy. Heterozygote patients most often remain asymptomatic.

Management and treatment

Prothrombin Complex Concentrates (PCCs) or fresh frozen plasma (if PCCs are not available) are usually used to treat hemorrhagic episodes. A plasma-derived FX concentrate is now available.

Prognosis

Prognosis is good with early diagnosis and adequate treatment.