ABSTRACT
BACKGROUND: Clotting factor II, or prothrombin, is a vitamin K-dependent proenzyme that functions in the blood coagulation cascade. Inherited factor II deficiency is an extremely rare autosomal recessive disorder affecting both genders: clinical bleeding can vary widely in homozygous individuals, and heterozygotes often remain clinically asymptomatic. This study highlights the rarity of inherited factor II deficiency and the importance of coagulation testing in the diagnosis of this condition. METHODS: We report four cases of factor II deficiency at our institution. RESULTS: At diagnosis, two patients were 3 days old, whereas the other two patients were 13 and 40 years of age. Three patients were female, and one was male. Symptoms of factor II deficiency were reported at referral in three patients; the deficiency was an incidental finding in the remaining case. The parents of all four patients were consanguineous (first degree). Factor II enzymatic activity was 1% in 3 cases and 5% in the incidental case. The treatment consisted of transfusion with fresh frozen plasma in all cases. CONCLUSIONS: The congenital deficiency of factor II is a rare inherited disorder. The diagnosis is mainly based on coagulation tests. However, the prognosis of this disease and access to medication are associated with the risk of occurrence of severe bleeding.
