Inherited deficiency of protein S in a Japanese family with recurrent venous thrombosis: a study of three generations

We found a new thrombophilic tendency in a family with protein S deficiency. The propositus, a 38-year-old Japanese man, is an offspring of consanguineous marriage and suffered from recurrent episodes of thromboembolism. Hemostatic studies, including platelet counts, platelet aggregation, assays of coagulation factors, and plasminogen activity were all within normal limits. The levels of antithrombin III, alpha 2-macroglobulin, protein C, and protein C inhibitor were also normal. However, functional protein S activity in plasma was markedly decreased (9%) in the propositus. The family study revealed that the reduced levels of functional protein S, less than 5% to 29% of normal (normal range: mean +/- 2 SD of 15 normal adults were 44 to 180%), were found in 11 members of this family over three generations. Six of 11 members had severe protein S deficiency (less than 5%), whereas five had partial deficiency. Four of eight adults with protein S deficiency had recurrent episodes of thrombosis. Immunologic levels of protein S antigen were variable in this family and did not correlate closely with the functional levels. These results suggest that the recurrent thrombotic disease in this family appears to be associated with an inherited deficiency of functional protein S.     

A new case of ''type II'' inherited protein S deficiency

Protein S inherited deficiency is associated with high risk of recurrent venous thrombotic disease (Broekmans et al, 1985a, b). Protein S exists as two forms in plasma, either free and functionally active or complexed with C4b-binding protein (C4b BP) and inactive (Dahibäck & Stenflo, 1981). We report here the case of a 26-year-old woman and her brother, 28 years old, both suffering from recurrent venous thrombosis since the age of 20, diagnosed as severe protein S deficiency according to the following data: free protein S: 2.5–3% by ELISA, undetectable by electroimmunodiffusion (BID); total protein S: 13–16% by ELISA, 21–18% by EID, C4b BP: normal levels. Crossed immunoelectrophoresis using anti-protein S antibodies revealed only traces of protein S associated with C4b BP and no free protein S. All these assays were performed in the absence of any anticoagulant therapy. Among the investigated relatives, less severe protein S deficiency was observed in three children of the propositus: total protein S levels ranging from 41% to 50% (EID), 40–53% (ELISA); free protein S levels ranging from 16% to 18% (EID), 10–12% (ELISA); normal C4b BP levels. Crossed immunoelectrophoresis revealed traces of free protein S but a significant amount of protein S associated with C4b BP. From these results, we consider, according to Comp's classification (Comp et al, 1986a), that the propositus and her brother are the second case of protein S deficiency type II to be reported in the literature while her children belong to the type I category.     

Definition of thrombophilia

Thrombophilia is characterized by clinical tendency to thrombosis or molecular abnomalities of hemostasis that predisposes to thromboembolic disease. Hereditary thrombophilia may be due to antithrombin deficiency, or protein C or protein S deficiency. More recently, other molecular abnormalities have been described: activated protein C resistance due to factor V Leiden, G 20210 A polymorphism on the prothrombin gene, increased factor VIII plasma levels or hyperhomocysteinemia. Acquired thrombophilia is frequently associated with the antiphospholipid syndrome characterized by thrombosis and presence of lupus anticoagulant or phospholipid-binding antibodies. In some cases, no molecular abnormality is found despite recurrent thrombosis observed in patient and his/her family. This situation can be considered as clinical thrombophilia.     

Familial thrombophilia due to a previously unrecognized mechanism characterized by poor anticoagulant response to activated protein C: prediction of a cofactor to activated protein C.

Although patients with thromboembolic disease frequently have family histories of thrombosis, well-defined defects such as inherited deficiencies of anticoagulant proteins are found only in a minority of cases. Based on the hypothesis that a poor anticoagulant response to activated protein C (APC) would predispose to thrombosis, a set of new coagulation assays was developed that measure the anticoagulant response in plasma to APC. A middle-aged man with a history of multiple thrombotic events was identified. The addition of APC to his plasma did not result in a normal anticoagulant response as measured by prolongation of clotting time in an activated partial thromboplastin time (APTT) assay. Four of the proband's relatives had medical histories of multiple thrombotic events, and they and several other family members responded poorly to APC in the APTT-based assay. Subnormal anticoagulant responses to APC were also found in factor IXa- and Xa-based assays. Several possible mechanisms for the observed phenomenon were ruled out, such as functional protein S deficiency, a protein C-inhibitory antibody, or a fast-acting protease inhibitor against APC. Moreover, restriction fragment-length polymorphism analysis excluded possible linkage of the underlying molecular defect to factor VIII and von Willebrand factor genes. We now describe a previously unrecognized mechanism for familial thromboembolic disease that is characterized by poor anticoagulant response to APC. This would appear to be explained best by a hypothesized inherited deficiency of a previously unrecognized cofactor to APC. As we have identified two additional, unrelated cases with thrombosis and inherited poor anticoagulant response to APC, this may constitute an important cause for familial thrombophilia.     

An abnormal plasma distribution of protein S occurs in functional protein S deficiency

Protein S is a natural anticoagulant present in the plasma that serves as a cofactor for activated protein C. Patients deficient in protein S are subject to recurrent venous thrombotic disease. Protein S deficiency differs from other plasma protein deficiencies in that deficient patients often have normal or only mildly reduced levels of protein S in their plasma as detected by conventional immunologic methods but have markedly reduced functional protein S levels. This apparent discrepancy is due to the presence of two forms of protein S in plasma. The protein S is present free and in a complex with C4b-binding protein. The free form is functionally active, whereas the bound form is not. Examination by crossed immunoelectrophoresis of 31 functionally protein S-deficient individuals from seven families reveals that 29 of the 31 have all or most of their protein S complexed to C4b-binding protein with little or no free protein and have correspondingly low levels of protein S functional activity (type I deficiency). Two related protein S-deficient individuals show a different type of distribution with little or no protein S, either bound or free (type II deficiency). The detection and classification of protein S-deficient individuals requires the application of both a functional assay and an assessment of protein S distribution between bound and free forms.     

Familial protein S deficiency with a variant protein S molecule in plasma and platelets

A protein S deficient family presenting a variant protein S molecule in plasma and platelets is described. The propositus, age 20, and two brothers suffered from venous thrombotic disease. The propositus, the only family member studied while taking oral anticoagulants, had a protein S antigen (ag) level of 17% and undetectable activity. As demonstrated by immunoblotting both the propositus and one clinically affected brother (42% ag, 7% activity) presented variant protein S molecules of 65,000 molecular weight (mol wt) while the other clinically affected brother (64% ag, 11% activity) had only protein S with normal electrophoretic mobility of 70,000 mol wt. The mother had normal protein S levels (93% ag, 100% activity) but had both normal and variant protein S molecules and based on her functional protein S data a normal anticoagulant activity of the variant molecule is suggested. One asymptomatic but protein S deficient sister (68% ag, 9% activity) as well as the asymptomatic protein S deficient father (59% ag, 10% activity) had only protein S molecules of 70,000 mol wt. The variant protein S bound to C4b-binding protein in plasma, and differed from normal protein S in carbohydrate content. Platelets of each family member contained the same immunoblotting pattern of normal and variant protein S forms as found in plasma, consistent with the hypothesis that protein S gene expression involves codominant expression of two alleles that is similar in cells that control the synthesis of both platelet and plasma forms of protein S.     

Identification and quantitation of protein S in human platelets

Gel filtered human platelets contaminated with less than 0.02% of plasma protein S contained 490 ng of protein S antigen per 3 X 10(8) platelets, equivalent to 2.5% of protein S in whole blood. Three patients with heterozygous plasma protein S deficiency, a congenital disorder associated with venous thrombotic disease, had platelet protein S antigen levels that were 40% of the mean platelet level in ten normal volunteers. In immunoblotting analysis, platelet protein S was indistinguishable from plasma protein S. Thrombin stimulation of platelets caused release of 63% of total protein S antigen and this release was abolished when platelets were preincubated with metabolic inhibitors. Thrombin effected limited proteolysis of platelet protein S and this reaction was inhibited by calcium ions. Immunofluorescent staining of platelets using protein S antibodies demonstrated that protein S colocalized with fibrinogen, an established alpha-granule protein. Thus, human platelets contain protein S in alpha granules that can be released by thrombin stimulation. The released protein S may bind to stimulated platelets and thereby promote and localize the anticoagulant activity of activated protein C on the platelet surface.     

Case report: portal vein thrombosis associated with hereditary protein C deficiency: a report of two cases

Protein C deficiency is one of the causes of curable or preventable portal vein thrombosis. We report two patients of portal vein thrombosis associated with hereditary protein C deficiency. The first patient presented with continuous right upper quadrant pain and high fever. The abdominal sonography revealed normal liver parenchyma but portal vein and superior mesenteric vein thrombosis. Based on a 55% (normal 70-140%) plasma protein C level, he was diagnosed as having protein C deficiency. A trace of his family history showed that his elder brother also had protein C deficiency with a 50% plasma C level. Both patients received anticoagulant therapy. The younger brother showed good response. Unfortunately, the elder one suffered from recurrent episodes of variceal bleeding and received a life-saving splenectomy and devascularization. We herein remind clinicians that early screening and therapy are helpful in preventing late complications of protein C deficiency with portal vein thrombosis.     

Risk factors of thromboembolism associated with pregnancy and the puerperium. Role of inherited and acquired thrombophilia

Thromboembolism in pregnancy and the puerperium and inherited or acquired thrombophilia are associated. Thrombophilia can be revealed by pregnancy. Thrombotic risk during pregnancy and the puerperium is higher in asymptomatic women with than without thrombophilia. Antithrombin deficiency, combined deficiencies and homozygous or double-heterozygotes factor V Leiden and factor II G 20210 A mutations are associated with a higher thrombotic risk than heterozygote mutations or protein S and C deficiencies, whereas hyperhomocysteinemia does not appear as a risk factor for maternal thromboembolic disease. Antiphospholipid syndrome with lupus anticoagulant is strongly associated with thrombotic risk in pregnancy and the puerperium. Further studies are required to assess the thrombotic risk in women with preeclampsia as well as early or late recurrent pregnancy loss.     

Free protein S levels are elevated in familial C4b-binding protein deficiency

In plasma, 40% of the protein S is free and functions as a cofactor for the anticoagulant effects of activated protein C. The remaining 60% of protein S is complexed to C4b-binding protein and is functionally inactive. A family with hereditary C4b binding protein deficiency has been identified with C4b-binding protein levels in an affected father and daughter of 37 micrograms/mL and 23 micrograms/mL, respectively; these values are significantly below the normal range for this protein of 180 micrograms/mL +/- 44 micrograms/mL (mean +/- 2 SD). The total protein S (free + bound) is normal in these individuals (23.2 micrograms/mL and 17.8 micrograms/mL, respectively; normal 19.1 micrograms/mL +/- 6.0 micrograms/mL). The free protein S levels are markedly increased at 22.5 micrograms/mL and 17.4 micrograms/mL, respectively (normal 5.9 micrograms/mL +/- 2.4 micrograms/mL). This experiment of nature shows that total protein S levels in plasma are not affected by the absence of C4b-binding protein and that chronic elevation of free protein S is not associated with increased hemorrhagic tendencies.     

Inherited heterozygous protein C deficiency and dysfunctional protein S with recurrent venous thrombotic diseases: a study of three generations of a Japanese family.

We describe a rare occurrence of a family affected with venous thrombosis, exhibiting a protein C (PC) deficiency and dysfunctional protein S (PS). The propositus and his father developed recurrent venous-thrombosis. Their PC deficiency was characterized by low levels of both antigen and activity, and their dysfunctional PS was suggested by low PS activities despite the presence of normal free PS antigen. Over three generations, six family members had a PC deficiency, and three had both a PC deficiency and a dysfunctional PS. The mode of inheritance of PC deficiency appears to be autosomal dominant.     

Oral contraceptives and gender affect protein S status

Protein S is a plasma protein that serves as a cofactor for the anticoagulant effects of activated protein C. Congenital protein S deficiency is often associated with thromboembolic disease. During pregnancy a decrease in the functional and antigenic levels of protein S occurs; this change in protein S status may contribute to the thromboembolic complications that sometimes occur during pregnancy. In certain patients, oral contraceptive use has also been associated with thrombotic complications. In this study, protein S status was determined in 21 women taking oral contraceptives and compared with that of 21 women not taking oral contraceptives and that of 21 men. The results show that women taking oral contraceptives have significantly lower total protein S (24.3 +/- 3.6 micrograms/mL; mean +/- SD) than women not taking oral contraceptives (28.6 +/- 3.9 micrograms/mL) (P less than .005). Men had significantly higher protein S levels (30.9 +/- 3.9 micrograms/mL, P less than .01) than age-matched women not taking oral contraceptives. In plasma, an equilibrium exists between free (functionally active) protein S and protein S complexed to C4b-binding protein, which is functionally inactive. The mean levels of C4b-binding protein were essentially the same among the three groups, but the levels of free protein S were significantly different and reflected different total protein S antigen levels. Additionally, we found that inflammation significantly elevated C4b-binding protein levels and could result in a further significant decrease in free protein S levels. These data indicate that plasma protein S levels are significantly affected by hormonal status and inflammation.     

Recurrent thromboembolism disclosing protein C deficiency. Apropos of a case with familial investigation

Every thromboembolic manifestation, especially in young subjects, calls for an aetiological study in which haemostasis is evaluated primarily with assays of physiological coagulation inhibitors: protein C, protein S and antithrombin III. Protein C deficiency is found in 6 to 7% of thromboembolic manifestations. We report the case of a 21-year old man who had phlebitis followed by pulmonary embolism without facilitating factors. Protein C level was 50% of normal value (0.50 IU/ml). The patient received heparin, subsequently replaced by oral anticoagulants after a long period of overlap between the two treatments. The outcome was favourable. Family investigation yielded a history of thromboembolic accidents in several members of the family, some of whom were protein C deficient (50% of normal value). Protein C synthesis is vitamin K-dependent. Protein C deficiency is transmitted as an autosomal dominant trait. Normal values range from 0.65 to 1.35 IU/ml. Clinically, 25% of the patients are said to be asymptomatic. The first thrombotic accidents occur in young subjects (mean age 29 +/- 14 years). Several points emerge from this case: full evaluation must be performed, especially in young subjects; family investigation consolidates the diagnosis and enables symptomatic protein C deficient patients to be treated and thrombotic manifestations to be prevented by effective anticoagulant therapy in high-risk situations; a prolonged period of heparin-oral anticoagulant overlap is needed to avoid cutaneous necrosis.     

Thrombosis in congenital deficiencies of AT III, protein C or protein S: a study of 44 children

Abstract. Congenital deficiency in coagulation inhibitors is a cause of hereditary thrombotic disease. The severity of symptoms is variable and depends on the type of deficit. In this paper, 44 children suffering from deep venous thrombosis, with a mean age of 5 years, were studied. A search for Lupus anticoagulant (LA) and coagulation inhibitor deficiency showed: 3/44 cases (6.8%) had protein S deficiency, 2/44 cases (4.5%) had protein C deficiency, 1/44 cases (2.3%) had deficiencies in both protein C and S; no cases of AT III deficiency and LA was positive in 2/44 cases (4.5%). Only 1 case of APC resistance out of 13 studied was found. Four family studies were performed and confirmed the congenital origin of the disorder.     

Thrombosis in congenital deficiencies of AT III, protein C or protein S: a study of 44 children

Abstract. Congenital deficiency in coagulation inhibitors is a cause of hereditary thrombotic disease. The severity of symptoms is variable and depends on the type of deficit. In this paper, 44 children suffering from deep venous thrombosis, with a mean age of 5 years, were studied. A search for Lupus anticoagulant (LA) and coagulation inhibitor deficiency showed: 3/44 cases (6.8%) had protein S deficiency, 2/44 cases (4.5%) had protein C deficiency, 1/44 cases (2.3%) had deficiencies in both protein C and S; no cases of AT III deficiency and LA was positive in 2/44 cases (4.5%). Only 1 case of APC resistance out of 13 studied was found. Four family studies were performed and confirmed the congenital origin of the disorder.     

Coagulation factor content of solvent/detergent plasma compared with fresh frozen plasma.

Solvent/detergent (S/D) plasma is being increasingly widely used in clinical practice, as it carries significantly lower risk of lipid-enveloped viral transmission than standard fresh frozen plasma (FFP). However, previous reports have suggested that S/D processing might influence the coagulation factor content of plasma. We have investigated this question by measuring procoagulant factors (fibrinogen, factor V and factor VIII), anticoagulant factors (protein C and protein S) and routine coagulation screening tests (prothrombin time and activated partial thromboplastin time) in 48 single-donor units of FFP, and in 16 units of S/D plasma (Octaplas). All routine coagulation screening tests, factor VII and protein C levels were within the normal reference range for both S/D plasma and FFP. However, we found significant reductions in factor V (31%), factor VIII (28%) and protein S (50%) in S/D plasma. The observed quantitative differences in coagulation factor levels may be further exacerbated by the lower volume of solvent detergent plasma units (200 ml) compared with units of standard fresh frozen plasma (250 ml). These findings are of potential clinical significance, particularly in those patients with liver disease, constitutional factor V deficiency and congenital or acquired protein S deficiency.     

Protein S and protein C Biochemistry, physiology, and clinical manifestation of deficiencies

Protein C and protein S are two plasma proteins that participate in an anticoagulant pathway. Protein C circulates as an inactive precursor that is converted to an active serine protease by a complex between thrombin and the endothelial cell-surface protein thrombomodulin. Activated protein C and protein S form an anticoagulant complex on cell surfaces that inactivates two of the regulatory proteins of coagulation, factors Va and VIIIa. Activated protein C is then cleared from the circulation by a relatively slow inactivation by ₁ antitrypsin and the protein C inhibitor. Deficiencies in protein C and protein S are associated with thrombotic complications. With protein S, this can arise as the result of a deficiency in protein S synthesis, proteolytic cleavage, and/or due to an increase in binding to the complement regulatory protein C4bBP, which behaves like an acute phase reactant. Inflammatory mediators not only elevate C4bBP levels, but also lead to downregulation of thrombomodulin expression. Animal experiments suggest that activated protein C and protein S may be effective and safe antithrombotic agents.     

Hereditary protein C deficiency: a review of the genetics, clinical presentation, diagnosis and treatment

Protein C (PC) is the central component of a major antithrombotic regulatory system with both anticoagulant and profibrinolytic properties. A deficiency of PC is one of several hereditary abnormalities of haemostatic proteins that have been described in patients with a propensity for thromboembolic complications. Major morbidity is often seen in these patients. The various aspects of hereditary PC deficiency in terms of clinical presentation, genetics, diagnosis and treatment of both homozygous and heterozygous states will be presented. In heterozygous deficiency, the levels of plasma PC are usually between 35% and 65% of normal, whereas the majority of normal individuals have levels between 70% and 130%. PC-deficient patients usually develop venous thrombotic complications between the ages of 15 and 40 years with a high incidence of DVT and pulmonary embolism. The majority of thrombotic lesions appear to develop spontaneously; others are associated with trauma, surgery or pregnancy. Treatment of symptomatic patients is initial heparin therapy followed by coumadin. After multiple thrombotic events, lifelong oral anticoagulant therapy is necessary. The potential complications of treatment are coumadin-induced skin necrosis, heparin-induced thrombocytopenia and bleeding. Homozygous PC deficiency, a rare but fatal hereditary condition, manifests itself with massive DIC and purpura fulminans in the newborn period. Effective treatment for these infants can be instituted with either oral anticoagulant therapy or PC replacement. The heterozygous deficiency of PC is similar to that found in other inherited disorders in that several genetic mechanisms are responsible for the expression of the disease. Both quantitative and qualitative decreases in PC exist, the former being type I deficiency and the latter, type II. The best initial diagnosis of either form involves a clotting (functional) assay while differentiation between the two also requires an antigenic (immunological) assay. Autosomal inheritance with significant variable penetrance is found with profound clinical implications. In summary, PC deficiency is one of a group of inherited disorders termed hereditary thrombotic disease, which may have serious implications for patient morbidity and mortality.     

Acquired free protein S deficiency associated with multiple myeloma: A case report

Investigation of recurrent venous thromboembolic events in a 46-year-old man with progressive IgG kappa (total serum IgG, 74.3 mg/ml) multiple myeloma revealed profound reductions in free protein S (PS) antigen (<0.1 U/ml) and PS activity (0.33 U/ml). Total PS antigen, protein C, antithrombin III, and C4b-binding protein levels were within normal limits. The patient had no family history suggestive of a congenital PS deficiency and no history of thrombosis predating the diagnosis of his plasma cell dyscrasia. Patient IgG was isolated from serum using a protein A-sepharose affinity column and characterized. PS-dependent clotting assays (Staclot Protein S, Diagnostica Stago, Asnleres sur-Seine, France) performed on normal pooled plasma mixed with dilutions of patient IgG (0.0–33.0 mg/ml) revealed a dose-dependent neutralization of PS activity by 43%. Total and free PS antigen levels were measured using Laurell rocket electroimmunodiffusion (Assera-Plate Protein S, Diagnostica Stago), which revealed a similar dose-dependent reduction in free PS antigen but preserved normal total PS antigen. Free PS antigen was reduced by 77% to 0.23 U/ml using an IgG concentration (16.5 mg/ml) less than one-fourth of that of the patient at time of serum collection. Specific binding of the patient IgG to commercially available purified human PS was demonstrated by Western Immunoblot analysis. Whereas acquired free PS deficiency has been previously reported in association with nephrotic syndrome, inflammatory bowel disease, HIV infection, and varicella infection, this is the first reported case of a hypercoagulable syndrome associated with acquired free PS deficiency and multiple myeloma. © 1996 Wiley-Liss, Inc.