Five female members of a family manifesting a dominantly inherited bleeding disorder were investigated for coagulation and platelet abnormalities. A long bleeding time, mild thrombocytopenia, large platelets, low platelet factor-3 activity (PF-3), and low factor VIII levels were found in the proband. Long bleeding times, low PF-3, and low factor VIII levels were found in various combinations in the four other family members studied. PF-3 was abnormal by three techniques in the proband and could be corrected by adding ADP. Her platelets and those of one other member did not aggregate when exposed to collagen. The proband’s platelets did not release ADP on collagen exposure. The severity of bleeding was proportional to the number of laboratory abnormalities in the individual’s studied. The findings in this family overlap both hereditary thrombopathia and von Willebrand’s disease and were quite variable between family members. It appears that there exists a spectrum of dominant hereditary bleeding disorders with abnormalities in the platelets or factor VIII levels or both, with variable expressivity in family members.
- Submitted September 28, 1971.
- Revision received March 9, 1972.
- Accepted March 12, 1972.
- © 1972 by American Society of Hematology, Inc.