Hereditary Giant Platelet Syndrome
Article first published online: 12 MAR 2008
British Journal of Haematology
Volume 29, Issue 4, pages 639–655, April 1975
How to Cite
Walsh, P. N., Mills, D. C. B., Pareti, F. I., Stewart, G. J., Margaret, D. E. M., Johnson, M. and Egan, J. J. (1975), Hereditary Giant Platelet Syndrome. British Journal of Haematology, 29: 639–655. doi: 10.1111/j.1365-2141.1975.tb02750.x
- Issue published online: 12 MAR 2008
- Article first published online: 12 MAR 2008
- Received 29 July 1974; accepted for publication 19 August 1974
Summary The platelets from two related patients with the hereditary giant platelet syndrome were examined. They were larger than normal but otherwise ultra-structurally normal; they contained increased storage pools of adenine nucleotides and heparin-neutralizing activity and took up serotonin at an increased rate. They aggregated normally with ADP and collagen but failed to aggregate with bovine factor VIII and Ristocetin. Some change in shape occurred with ADP, and the reduction in adenylate energy change after addition of ADP to platelet-rich plasma was smaller than normal.
Platelet coagulant activities including contact product forming activity, intrinsic factor-Xa forming activity and platelet factor 3 activity were normal or increased, but collagen-induced coagulant activity was absent whether tested in washed platelet suspensions or platelet-rich plasma. Platelet washing experiments showed decreased binding of factors V and VIII to hereditary giant platelets and no detectable factor XI in washed platelet suspensions. It is concluded that (1) the hereditary giant platelets studied lacked a binding mechanism for factors V, VIII and XI; (2) the normal development of collagen-induced coagulant activity apparently depends upon the binding of factor XI to the platelet membrane; and (3) the defective prothrombin consumption observed in these patients may have resulted from the failure of their platelets to bind factor XI.