Factor VI359T: a novel mutation associated with thrombosis and resistance to activated protein C
We report a kindred in which two siblings suffered spontaneous venous thromboses in the second decade of life. Further investigation showed reduced coagulation factor V (FV) activity and activated protein C resistance (APCR) ratio but no other thrombophilic abnormalities. The reduction in APCR ratio persisted in a modified APCR assay in which FV activity was normalized between test and control pla