PLASMA HOMOCYSTEINE ASSAY IN THE EXPLORATION OF THROMBOSIS IN YOUNG SUBJECTS

Homocystinuria is a rare inherited metabolic disease transmitted as an autosomal recessive trait. Arterial and venous thromboembolic events are frequent and life-threatening complications in homocystinuric patients. It has been suggested that mild homocysteinemia could be a risk factor for vascular disease. We measured total plasma L-homocysteine concentrations by radioisotopic assay in 32 subjects with arterial (n = 15) or venous (n = 17) thrombosis. Twelve subjects exceeded the upper normal limit (2,70 SD above the mean), i.e. 14.1-mu-mol/l. Seven had arterial thrombotic disease and five had deep vein thrombosis. In 18 subjects thrombosis developed in the absence of any of the hiterto recognized risk factors; 6 of these subjects had mild homocysteinemia. Thus, homocysteine metabolism must be investigated in patients with thromboembolism. An increase of homocysteinemia could be a risk factor for thromboembolic events, and the possible benefit of vitamin therapy should be discussed.