FACTOR XII (FXII)

Most affected individuals with FXII deficiency are asymptomatic and have rarely a mild tendency to bleed. However, they can show an impaired fibrinolysis, which can expose them to thrombosis.
Since bleeding time is usually normal, diagnosis is characterized by a prolonged activated partial thromboplastin time (aPTT) test. A specific FXII assay helps to confirm the diagnosis.