A family with heterozygous factor X friuli defect outside friuli

Abstract
Three members of the same family were found to have a clotting defect consistent with the diagnosis of heterozygous factor X Friuli disorder. The main features of the defect were a mild prolongation of prothrombin time and partial thromboplastin time, but a normal Stypven-Cephalin clotting time. Factor X activity was 40–50% of normal using tissue thromboplastin, but was perfectly normal using Russell's viper venom and cephalin. Using chromogenic substrate S-2222 the level was 30% of normal. Immunologically, factor X was normal. Bleeding manifestations were mild if any. The hereditary pattern was autosomal. The family comes from an area far away from Friuli and represents the first example of factor X Friuli discovered outside the Friuli.