Hereditary deficiency of Factor V may be associated with a clinical bleeding disorder.


Synonym: parahemophilia


Inheritance: autosomal recessive (siblings affected and consanguinity in family) or autosomal dominant (parents and sibling affected)


Clinical findings:

(1) abnormal bruising

(2) epistaxis

(3) soft tissue hematomas

(4) occasionally hemarthroses

(5) CNS hemorrhage

(6) bleeding from the umbilical stump after delivery

(7) menorrhagia (if female)

(8) excessive bleeding after dental extraction

(9) excessive bleeding following surgery or trauma


A mild to moderate deficiency may be asymptomatic.


Laboratory features (assuming no factor replacement):

(1) prolonged PT

(2) prolonged PTT

(3) normal thrombin time

(4) low levels of Factor V antigen and/or activity

(5) normal levels of Factor VIII antigen and activity


Differential diagnosis:

(1) hemophilia A or B

(2) combined hereditary deficiency of Factors V and VIII

(3) acquired deficiency of Factor V


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