Abstract
Two cases of siblings with congenital factor V deficiency were reported. In their family history paternal grandmother died of hemorrhagic tendency.
1) Case I, K. M., a 16 year-old boy was admitted because of bleeding, such as recurrent and continuous epistaxis. Screening test of coagulation revealed prolongation of whole blood clotting, recalcification, plasma prothrombin and partial thromboplastin times. Factor V activity was greatly depressed from 2.2 to 8%.
2) Case II, A. M., a 8 year-old girl, a sister of the above mentioned boy, had suffered from hemorrhagic tendency such as hematoma or petechiae formation by insect stick or bruise and epistaxis from her newborn period. Coagulation tests demonstrated almost the same data as her brother, showing depressed activity of factor V to 7.5%.
