[Protein-S deficiency in young patients with thrombotic brain infarction].

The observation of protein S deficiency in a family six members of which had recurrent cerebral strokes prompted a prospective study so far including 33 patients (23 women, 10 men) with cerebral arterial thrombosis at the age of 19 to 57 years (mean 31 years) admitted to the neurological departments of several hospitals. Diseases associated with cerebral arterial occlusions, such as arterial embolism or hematological, infectious and immunological disorders were not found. The following parameters were tested: antithrombin III, protein C, plasminogen, fibrinolytic capacity after infusion of DDAVP, and free and total protein S. Prothrombin times of all patients were within normal ranges; no woman had taken oral contraceptives for at least 3 months before examination. In 9 patients (8 women, 1 man) a decrease of free and total protein S was found; in 4 additional patients (2 women, 2 men) only the free protein S was reduced. Protein S deficiency was confirmed as an inherited defect in 5 cases by family studies, but excluded in one (both parents normal). Protein S deficiency was combined with protein C deficiency in 3 cases, plasminogen deficiency in 2 cases and reduced fibrinolytic capacity in two. Venous thromboembolism occurred only in one of the 13 patients with protein S deficiency and cerebral arterial thrombosis. Protein S deficiency may be found-mainly as a familial trait-in a substantial percentage of younger patients with "idiopathic" cerebral arterial thrombosis.