The inherited disease hereditary haemorrhagic telangiectasia (HHT) causes bleeding from dilated fragile vessels, particularly in the nose and gut.

However, many HHT patients develop deep venous thromboses and/or pulmonary embolism, necessitating treatments with anticoagulants that further impair control of their haemorrhagic state. Our initial observations using general coagulation tests suggest that the blood of HHT patients is intrinsically hypercoagulable.

We hypothesize that the genetically-determined abnormality in the blood vessels of HHT patients leads to alteration in the concentrations or activity of one or several of the proteins which affect blood clotting leading to a hypercoagulable state.

We propose to study levels and activity of blood coagulation factors in people with hereditary haemorrhagic telangiectasia and in normal volunteers. This should define the significance and basis for our initial observations, and will have significant implications for the clinical management of HHT patients.