title: Congenital factor X deficiency in Japan.
abstract: Congenital factor X deficiency is a very rare inherited coagulation abnormality. There have been reported 43 cases of this disorder in the world and only 2 cases in Japan. Recently, we have hemostatically and immunologically examined as many as 3 cases of this rare disease, 18-year-old male, 11-year-old male and 6-year-old female. Hemostatic examinations revealed prolonged prothrombin time, partial thromboplastin time and decreased serum thromboplastic activity in these 3 cases. Stypven-cephalin clotting time was also abnormal. Factor X activities of our cases were low when assayed by either tissue thromboplastin and partial thromboplastin or by Stypven-cephalin mixture, which were 2.6, 1.5 and 4.5%, respectively. The half lives of infused factor X were 24, 38.6 and 56 hr, respectively, which are consistent with the data of other authors. Immunological assay of factor X (radioimmunoassay) showed 0.47 microgram/ml in the second case and 0.15 microgram/ml in the third case, from which our cases were considered to be classical factor X deficiency.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001777:Blood Coagulation; D002648:Child; D005171:Factor X Deficiency / Q000097:blood / Q000151:congenital* / Q000235:genetics; D005260:Female; D005838:Genotype; D006487:Hemostasis; D006801:Humans; D007020:Hypoprothrombinemias / Q000151:congenital*; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time