Venous thrombosis associated with pernicious anaemia. A report of two cases and review.

Since homocystinuria, an inborn metabolism error is complicated by venous thrombosis in about half of the patients, hyperhomocysteinemia has been suspected of favouring thrombosis. Several case-control studies and even meta-analysis have confirmed a link between venous thrombosis and mild hyperhomocysteinemia. Nevertheless, the proper role of homocysteine remains debated. Hyperhomocysteinemia is induced by vitamin B9 or B12 deficiencies in a vast majority of cases. The authors report on two patients with venous thrombosis revealing pernicious anemia and review nine similar cases found in the world literature. The literature concerning the relationships between homocysteine and venous thrombosis is briefly reviewed.