Factor V haemostatic diathesis impairing thrombin activation, membrane binding and circulating antigen level due to a novel compound heterozygous mutation, Leu1821Ser and Gly2192Cys

Introduction Congenital factor V (FV) deficiency is a rare clotting disorder affecting ∼1 in 1,000,000, with bleeding severity that ranges broadly for poorly understood reasons. Aim To help understand the molecular basis of the observed phenotype in FV deficient patients, the genetics and biochemistry causing a patient's FV deficiency were evaluated. Methods and Results A 71‐year‐old female, who had serious life‐long bleeding upon provocation and profound menorrhagia that lead to hysterectomy, was found to have 3% of normal plasma FV antigen with normal electrophoretic mobility. Platelet FV was similarly low, although the banding pattern was less fragmented than normal. Plasma clotting activity was