Congenital Deficiency of Blood Clotting Factors II, VII, IX, and X

Abstract

A patient congenitally deficient in factors II, VII, IX, and X has been further investigated after a follow-up of 15 yr. At birth, these factors, when determined by clotting assays, were undetectable. Following therapy with vitamin K1, the clotting activity of these factors rose but never exceeded 18% of normal. Immunologic assays revealed much higher levels of these factors than did clotting assays, thus suggesting that the vitamin-K-dependent factors were present in abnormal forms. Two-dimensional crossed Immunoelectrophoresis showed that at least two forms of prothrombin were present in the patient's plasma. One form was similar to normal prothrombin; the other had the same mobility as acarboxyprothrombin. In addition, the majority of this fast-migrating peak was not adsorbable onto insoluble barium salts. These observations suggested that some molecules of the patient's prothrombin lacked the normal complement of gamma-carboxyglutamic acid residues. This observation was confirmed by a specific assay for gammacarboxyglutamate. Since malabsorption of vitamin K, warfarin intoxication, and hepatic dysfunction were excluded as causes of this patient's syndrome, this rare congenital abnormality could represent either a defective gamma-carboxylation mechanism within the hepatocyte or faulty vitamin K transport.