Congenital Deficiency of Proconvertin : A Clinical

With the technical assistance of Mary Jane Patch D ESPITE THE FACT that SOIll 65 cases of congenital deficiency of proconvertin have been reported, there still remains considerable confusion regarding the nature of the defect, its effect on the coagulation mechanism and the classification of these cases. It is the generally accepted 2 that proconvertin ( factor VII, SPCA, stable factor, co-thromboplastin ) is necessary for normal coagulation to occur and that it is an accelerator of the conversion of prothrombin to thrombin.3 Recently Ackroyd4 restudied a case of congenital factor VII deficiency, originally reported by Jenkins in which he found normal intrinsic coagulation when measured by all the currently available procedures. He concluded that the function of factor Vii is obscure and that it apparently played no role in normal coagulation, but that it nlight be essential for normal hemostasis. A related disorder, Stuart factor deficiency, only recently delineated from the group by Hotigie et al.,7 has further complicated matters because of the many similarities in the results obtained from laboratory studies in the two types of cases. Many investigators have restudied some of the earlier cases and assigned them to one or the other category.8’#{176} Indeed, one well studied case has now been reported on three occasions,10 with a new diagnosis offered each time. Recently we had the opportunity to investigate a case of congenital proconvertin deficiency in a Hopi Indian. Although the child had a moderately severe hemorrhagic tendency since birth, similar results to those noted by Ackroyd were found: namely, essentially normal intrinsic coagulation despite the absence of detectable levels of proconvertin by the methods currently available. The rarity of this type of coagulation disorder prompted the following case report.