Bleeding manifestations in heterozygotes with congenital FVII deficiency: a comparison with unaffected family members during a long observation period*

Objectives: To determine whether heterozygotes with FVII deficiency have a bleeding tendency or not. Patients and methods: Eighty-four patients (OK) heterozygous for FVII deficiency, at the onset of the study, were paired with unaffected family members and followed for a long period of time (mean 22.6 years) for the occurrence of bleeding. Diagnosis of heterozygosis had to be based on family studies, clotting, immunological assays and genetic analysis. Results: The mean FVII activity level was 0.51 IU/dl (range 35–65) and 94 IU/dl (range 88–118) in the heterozygotes and in the normal counterparts, respectively. Documented bleeding manifestations occurred in eight heterozygotes and in seven normal subjects. Statistical analysis of the difference was not significant. Bleeding manifestations were easy bruising, bleeding after tooth extractions, menorrhagia, epistaxis with no difference among the two groups. There was no strict correlation between bleeding and FVII activity levels. Conclusions: The study indicates that heterozygotes for FVII deficiency show rare bleeding manifestations which are also present in the unaffected family members with normal FVII levels. This indicates that Factor VII activity levels played no role in the occurrence of the bleeding symptoms. Furthermore, FVII levels of around 0.40 IU/dl are capable of assuring a normal hemostasis.