[Hereditary protein S deficiency responsible for digestive vascular thrombosis].

Protein S is a physiological inhibitor of coagulation. It intervenes as co-factor of activated protein C and increases the inactivation of factors V and VIII induced by the latter. Patients with protein S deficiency are exposed to recurrent venous and arterial thrombosis. Most of these thromboses affect the lower limbs, but other regions, and notably the digestive tract, may be involved. Deficiencies in physiological inhibitors of coagulation, and in particular protein S, seem to be a new entity in the vascular pathology of the gastrointestinal system. All young patients with thromboembolic accidents affecting the digestive tract should be investigated for protein S deficiency. If such deficiency is found, then all members of the patients' family must also be investigated. Long-term treatment with antivitamin K drugs prevents recurrences of these thromboembolic accidents.