Hypercoagulability state is the result of the interplay of genetic predisposition and risk factors. Many key enzymes and reactions in coagulation and anti-coagulation system are involved. Hereditary antithrombin deficiency is one of the major risk factors of venous thromboembolic disease (VTE), whereas hyperhomocysteinemia may also play a role. This article reviews the recent researches on the contributions of these two factors to VTE.
Antithrombin III Deficiency ; complications ; Humans ; Hyperhomocysteinemia ; complications ; Venous Thrombosis ; etiology

Antithrombin and protein C are two crucial members in the anticoagulant system and play important roles in hemostasis. Mutations in SERPINC1 and PROC lead to deficiency or dysfunction of the two proteins, which could result in venous thromboembolism (VTE). Here, we report a Chinese 22-year-old young man who developed recurrent and serious VTE in cerebral veins, visceral veins, and deep veins of the lower extremity. Laboratory tests and direct sequencing of PROC and SERPINC1 were conducted for the patient and his family members. Coagulation tests revealed that the patient presented type I antithrombin deficiency combined with decreased protein C activity resulting from a small insertion mutation c.848_849insGATGT in SERPINC1 and a short deletion variant c.572_574delAGA in PROC. This combination of the two mutations was absent in 400 healthy subjects each from southern and northern China. Then, we summarized all the mutations of the SERPINC1 and PROC gene reported in the Chinese Han population. This study demonstrates that the combination of antithrombin deficiency and decreased protein C activity can result in severe VTE and that the coexistence of different genetic factors may increase the risk of VTE.
Antithrombin III ; genetics ; Antithrombin III Deficiency ; etiology ; genetics ; China ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Pedigree ; Protein C ; genetics ; metabolism ; Venous Thromboembolism ; complications ; genetics ; Young Adult

The prevalences of deficiencies in antithrombin III (AT III), protein C (PC), protein S (PS) and in the activated protein C (APC) resistance in the thrombotic population of the Trakya region, Turkey were investigated. 37 patients with venous thrombosis (VT) and 17 patients with arterial thrombosis (ArT) were included in this study. The mean ages of the patients with VT and ArT were 46 years (range 20-70) and 38 years (range 32-40), respectively. The activity of AT III was measured by commercially available immuno-turbidimetric assay. The activities of PC and PS were determined by coagulometric assay. The APC resistance was measured using a modified APTT-based clotting assay. Among the VT patients, there were 2 cases (5.4%) with AT III, 5 (13.51%) with PC deficiency, 5 (13.51%) with PS deficiency and 2 (5.4%) with APC resistance. In the ArT patient group, there was 1 patient (5.88%) with AT III, 3 (17.64%) with PC deficiency, 1 (5.88%) with PS deficiency and no APC resistant patients, while there was one (2.08%) with PC deficiency and one (2.08%) with APC resistance in the control group (49 persons, mean age 41 years). The relative risk of thrombosis (odds ratio) was 1.7 in the deficiency of PC and 5.6 in the deficiency of PS. The data presented suggests that the prevalences of AT III, PC and PS deficiencies causing thrombophilia in the Trakya region of Turkey are higher than in other reported studies while the APC resistance is lower than in others. Further studies including more patients would be required to clarify these discrepancies.
Activated Protein C Resistance/complications ; Adult ; Antithrombin III Deficiency/complications ; Human ; Middle Age ; Prevalence ; Protein C Deficiency/complications ; Protein S Deficiency/complications ; Risk Factors ; Thrombophilia/epidemiology* ; Thrombosis/etiology ; Turkey/epidemiology

OBJECTIVETo investigate the mechanism of anticoagulation protein defect in the pathogenesis of unexplained recurrent miscarriage.

METHODSFifty-seven patients with a history of unexplained abortion were enrolled as the investigation group for tests of protein C, protein S, antithrombin III (AT-III), as well as activated protein C resistance (APC-R). The control group consisted of fifty healthy women with a history of normal pregnancy and delivery. Blood samples were obtained for, measuring serum activity of protein C, protein S, AT-III, and APC-R. Patients with positive APC-R were tested for factor V (FV) Leiden gene mutation by PCR-RFLP method.

RESULTSOf the 57 patients, 12 (21.1%), 1 (1.8%), and 5 (8.8%) cases were found with protein S, protein C, and AT-III deficiency respectively, and 13 (22.8%) cases with positive results of APC-R. Of the control group, no protein C or AT-III deficiency was ever found, whereas 2 (4.0%) volunteers were presented with protein S deficiency and 3 (6.0%) with positive results of APC-R. No FV Leiden gene mutation was identified in all the patients with positive APC-R results. Late spontaneous abortion cases had higher incidence of anticoagulation protein defect than the early cases.

CONCLUSIONAnticoagulation protein defect may play a role in the pathogenesis of fetal loss, especially for those occurring in late stage of pregnancy.

Abortion, Habitual ; blood ; etiology ; Activated Protein C Resistance ; blood ; complications ; genetics ; Adult ; Antithrombin III ; metabolism ; Antithrombin III Deficiency ; blood ; complications ; Factor V ; genetics ; Female ; Humans ; Point Mutation ; Protein C ; metabolism ; Protein C Deficiency ; blood ; complications ; Protein S ; metabolism ; Protein S Deficiency ; blood ; complications