factor X deficiency
Deficiencies of Factor's II, V and X are inherited as autosomal recessives. They occur rarely with reported incidences between 1 in 500 000 to 1 in 1 000 000, and result from the production of altered inactive forms of the relevant protein.
Laboratory tests show increased prothrombin and partial thromboplastic times - not corrected by administration of vitamin K; other tests are normal.
Diagnosis is by specific factor assay.
Acquired deficiencies of these diseases may result from:
- antibodies to the appropriate Factor
- lupus anticoagulants - e.g. systemic lupus erythematosus
- systemic amyloidosis - amyloid fibrils bind to Factor X
- descriptive name for factor II is prothrombin
- descriptive name for factor V is labile factor
- descriptive name for factor X is Stuart-Power factor
Last reviewed 01/2018