Factor Xi Deficiency, also known as plasma thromboplastin antecedent deficiency, is related to hemophilia and vitamin k deficiency bleeding. An important gene associated with Factor Xi Deficiency is F11 (Coagulation Factor XI), and among its related pathways/superpathways are Infectious disease and Response to elevated platelet cytosolic Ca2+. The drugs Heparin, bovine and Apixaban have been mentioned in the context of this disorder. Affiliated tissues include skin and liver, and related phenotypes are abnormal bleeding and reduced factor xi activity