Inheritance: autosomal recessive, with consanguinity common in affected families
Clinical features if mild (Factor X levels >= 15%):
(1) bleeding during surgery or major trauma
(2) bleeding during childbirth (if female)
Clinical features if severe:
(1) retroperitoneal hematoma
(2) hemarthroses, which may be crippling
(3) soft tissue hematomas and/or pseudotumors
(4) intracerebral hemorrhage
(5) hematuria
(6) menorrhagia (if female)
Laboratory findings (assuming no factor replacement):
(1) prolonged PT
(2) prolonged aPTT
(3) normal thrombin time
(4) Russell viper venom test may be normal or prolonged
(5) reduced Factor X levels
Differential diagnosis:
(1) other severe hereditary coagulation defects with hemarthroses
(2) acquired Factor X deficiency
