[Recurrent thrombophlebitis and ulcera crurum as manifestations of hereditary blood coagulation disorders and Klinefelter syndrome. Discussion based on 4 case examples].

Recurrent phlebothromboses in young patients with subsequent severe postthrombotic syndrome and chronic venous leg ulcers may be caused by underlying hereditary disorders of hemostasis or may occur as part of other congenital syndromes. The most common hereditary disorders of hemostasis in this respect appear to be deficiencies of antithrombin III, protein C, and protein S, and activated protein C resistance (mutations of factor V). Less frequently, dysfibrinogenemia, increased plasminogen activator inhibitor levels, or deficiencies of tissue plasminogen activator or heparin cofactor II may be found. Klinefelter's syndrome and homocystinuria are prime examples of those rare congenital disorders indirectly associated with an elevated risk of thrombosis in young individuals. Early diagnosis of these disorders will allow timely treatment, preventive care and counselling of patients as well as family members.