Antithrombin Deficiency Research Articles

Evolving Knowledge on Primary and Secondary Prevention of Venous Thromboembolism in Carriers of Hereditary Thrombophilia: A Narrative Review

The association between heritability of venous thromboembolism (VTE) and thrombophilia was first reported clinically in 1956, later followed by the first description of a congenital cause of hypercoagulability-antithrombin deficiency-in 1965. Since then, our knowledge of hereditary causes of hypercoagulability, which may predispose carriers to VTE has improved greatly. Novel genetic defects responsible for severe thrombophilia have been recently identified and we have learned that a wide range of interactions between thrombophilia and other genetic and acquired risk factors are important determinants of the overall individual risk of developing VTE. Furthermore, therapeutic strategies in thrombophilic patients have benefited significantly from the introduction of direct oral anticoagulants. The present review is an overview of the current knowledge on the mechanisms underlying inherited thrombophilia, with a particular focus on the latest achievements in anticoagulation protocols and prevention strategies for thrombosis in carriers of this prothrombotic condition.

Factors Contributing to the Risk of Venous Thromboembolism

Both the deep vein thrombosis and pulmonary embolism are classified into venous thromboembolism (VTE). Risk factors for VTE are multifactorial with both genetic and non-genetic risk factors. Factor V Leiden, Prothrombin, and ABO blood group are three widely researched mutations highly associated to VTE while there are other rarer genetic risk factors such as Protein C, Protein S, Antithrombin deficiencies. Race and ethnicity, age, sex, diet and lifestyle are examples of some of the non-genetic risk factors for VTE; however, because non-genetic risk factors may be dependent of other environmental factors (such as the relationship between sex and oral contraceptives), their individual association to VTE needs further research.

A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial of Preoperative Antithrombin Supplementation in Patients at Risk for Antithrombin Deficiency After Cardiac Surgery.

Antithrombin (AT) activity is reduced during cardiac operations with cardiopulmonary bypass (CPB), which is associated with adverse outcomes. Preoperative AT supplementation, to achieve >58% and <100% AT activity, may potentially reduce postoperative morbidity and mortality in cardiac operations with CPB. This prospective, multicenter, randomized, double-blind, placebo-controlled study was designed to evaluate the safety and efficacy of preoperative treatment with AT supplementation in patients at risk for low AT activity after undergoing cardiac surgery with CPB. A total of 425 adult patients were randomized (1:1) to receive either a single dose of AT (n = 213) to achieve an absolute increase of 20% above pretreatment AT activity or placebo (n = 212) before surgery. The study duration was approximately 7 weeks. The primary efficacy end point was the percentage of patients with any component of a major morbidity composite (postoperative mortality, stroke, acute kidney injury [AKI], surgical reexploration, arterial or venous thromboembolic events, prolonged mechanical ventilation, and infection) in the 2 groups. Secondary end points included AT activity, blood loss, transfusion requirements, duration of intensive care unit (ICU), and hospital stays. Safety was also assessed. Overall, 399 patients (men, n = 300, 75.2%) with a mean (standard deviation [SD]) age of 66.1 (11.7) years, with the majority undergoing complex surgical procedures (n = 266, 67.9%), were analyzed. No differences in the percentage of patients experiencing morbidity composite outcomes between groups were observed (AT-treated 68/198 [34.3%] versus placebo 58/194 [29.9%]; P = .332; relative risk, 1.15). After AT infusion, AT activity was significantly higher in the AT group (108% [42-143]) versus placebo group (76% [40-110]), and lasted up to postoperative day 2. At ICU, the frequency of patients with AT activity ≥58% in the AT group (81.5%) was significantly higher ( P < .001) versus placebo group (43.2%). Secondary end point analysis did not show any advantage of AT over placebo group. There were significantly more patients with AKI ( P < .001) in the AT group (23/198; 11.6%) than in the placebo group (5/194, 2.6%). Safety results showed no differences in treatment-emergent adverse events nor bleeding events between groups. AT supplementation did not attenuate adverse postoperative outcomes in our cohort of patients undergoing cardiac surgery with CPB.

Long-Read Sequencing Identifies the First Retrotransposon Insertion and Resolves Structural Variants Causing Antithrombin Deficiency.

The identification of inherited antithrombin deficiency (ATD) is critical to prevent potentially life-threatening thrombotic events. Causal variants in SERPINC1 are identified for up to 70% of cases, the majority being single-nucleotide variants and indels. The detection and characterization of structural variants (SVs) in ATD remain challenging due to the high number of repetitive elements in SERPINC1 . Here, we performed long-read whole-genome sequencing on 10 familial and 9 singleton cases with type I ATD proven by functional and antigen assays, who were selected from a cohort of 340 patients with this rare disorder because genetic analyses were either negative, ambiguous, or not fully characterized. We developed an analysis workflow to identify disease-associated SVs. This approach resolved, independently of its size or type, all eight SVs detected by multiple ligation-dependent probe amplification, and identified for the first time a complex rearrangement previously misclassified as a deletion. Remarkably, we identified the mechanism explaining ATD in 2 out of 11 cases with previous unknown defect: the insertion of a novel 2.4 kb SINE-VNTR-Alu retroelement, which was characterized by de novo assembly and verified by specific polymerase chain reaction amplification and sequencing in the probands and affected relatives. The nucleotide-level resolution achieved for all SVs allowed breakpoint analysis, which revealed repetitive elements and microhomologies supporting a common replication-based mechanism for all the SVs. Our study underscores the utility of long-read sequencing technology as a complementary method to identify, characterize, and unveil the molecular mechanism of disease-causing SVs involved in ATD, and enlarges the catalogue of genetic disorders caused by retrotransposon insertions.

Platelet dysfunction after trauma: From mechanisms to targeted treatment.

Platelet dysfunction after trauma: From mechanisms to targeted treatment.

Association of Changes in Antithrombin Activity Over Time With Responsiveness to Enoxaparin Prophylaxis and Risk of Trauma-Related Venous Thromboembolism

Venous thromboembolism (VTE) affects 2% to 20% of recovering trauma patients, despite aggressive prophylaxis with enoxaparin. Antithrombin is a primary circulating anticoagulant and crucial component of enoxaparin thromboprophylaxis. Approximately 20% of trauma patients present with antithrombin deficiency (antithrombin activity <80%). To examine time-dependent changes in antithrombin activity, responsiveness to enoxaparin, as measured by anti-factor Xa (anti-FXa) levels, and incidence of VTE after severe trauma and to assess the association of ex vivo antithrombin supplementation with patients' sensitivity to enoxaparin prophylaxis. This single-center, prospective cohort study was performed at a level 1 trauma center between January 7, 2019, and February 28, 2020. Adult trauma patients admitted to the trauma service at high risk for VTE, based on injury pattern and severity, were screened and enrolled. Patients who were older than 70 years, were pregnant, had a known immunologic or coagulation disorder, or were receiving prehospital anticoagulants were excluded. Blood samples were collected on emergency department arrival and daily for the first 8 days of hospitalization. Patients' antithrombin activity and anti-FXa levels were measured by a coagulation analyzer, and thrombin generation was measured by calibrated automated thrombography. Responsiveness to enoxaparin was assessed by measuring anti-FXa levels 4 to 6 hours after the first daily enoxaparin dose and compared between patients who developed VTE and who did not. In addition, the associations of ex vivo supplementation of antithrombin with plasma anti-FXa levels were assessed. Among 150 patients enrolled (median [IQR] age, 35 [27-53] years; 37 [24.7%] female and 113 [75.3%] male; 5 [3.3%] Asian, 32 [21.3%] Black, and 113 [75.3%] White; and 51 [34.0%] of Hispanic ethnicity), 28 (18.7%) developed VTE. Patients with VTE had significantly lower antithrombin activity on admission compared with patients without VTE (median [IQR], 91% [79%-104%] vs 100% [88%-112%]; P = .04), as well as lower antithrombin activity on hospital days 5 (median (IQR), 90% [83%-99%] vs 114% [99%-130%]; P = .011), 6 (median [IQR], 97% [81%-109%] vs 123% [104%-134%]; P = .003), 7 (median [IQR], 82% [74%-89%] vs 123% [110%-140%]; P < .001), and 8 (median [IQR], 99% [85%-100%] vs 123% [109%-146%]; P = .011). Anti-FXa levels were significantly lower in patients with VTE vs those without VTE at hospital day 4 (median [IQR], 0.10 [0.05-0.14] IU/mL vs 0.18 [0.13-0.23] IU/mL; P = .006), day 6 (median [IQR], 0.12 [0.08-0.14] IU/mL vs 0.22 [0.13-0.28] IU/mL; P = .02), and day 7 (median [IQR], 0.11 [0.08-0.12] IU/mL vs 0.21 [0.13, 0.28] IU/mL; P = .002). Multivariable analyses found that for every 10% decrease in antithrombin activity during the first 3 days, the risk of VTE increased 1.5-fold. The results of this cohort study suggest that after severe trauma, antithrombin deficiency is common and contributes to enoxaparin resistance and VTE. Interventional studies are necessary to determine the efficacy of antithrombin supplementation in the reduction of VTE incidence.

Utility of the SERPINC1 Gene Test in Ischemic Stroke Patients With Antithrombin Deficiency

ObjectiveAntithrombin (AT) plays a critical role in the coagulation system, and its deficiency induces hypercoagulability. AT deficiency is caused not only by inherited variants in the SERPINC1 gene but also by acquired conditions. Therefore, AT deficiency alone could not ensure the presence of the SERPINC1 mutation. We evaluated the utility of the SERPINC1 gene test in ischemic stroke, an important clinical type of arterial thrombosis.MethodsThis retrospective, observational study investigated symptomatic patients who underwent the SERPINC1 gene test because of decreased AT activity (<80%) during 2009-2021 at a tertiary hospital. For the detection of sequence variants in the SERPINC1 gene, direct Sanger sequencing and multiplex ligation-dependent probe amplification were performed. The phenotypes of patients with SERPINC1 gene mutations were examined, and the conditions associated with the pathogenic variants were analyzed.ResultsIn our cohort (n = 19), 13 of 19 patients (68.4%) had the pathogenic variant of the SERPINC1 gene. Ischemic stroke (n = 7) was significantly associated with the pathogenic variants (p = 0.044), and the pathogenicity detection rate was 100%. For any kind of arterial thrombosis (n = 8), the detection rate of the pathogenic variant was 87.5%, but was not statistically significant (p = 0.177). The detection rates of the pathogenic variant in ischemic stroke or arterial thrombosis groups were both higher than those in the venous thrombosis-only group (54.5%).ConclusionThe SERPINC1 gene test was useful in determining the cause of AT deficiency-related arterial thrombosis, especially ischemic stroke. We propose the diagnostic flow of SERPINC1-related ischemic stroke.

Two SERPINC1 variants affecting N-glycosylation of Asn224 cause severe thrombophilia not detected by functional assays

AbstractAntithrombin deficiency, the most severe congenital thrombophilia, might be underestimated, as some pathogenic variants are not detected by routine functional methods. We have identified 2 new SERPINC1 variants, p.Glu227Lys and p.Asn224His, in 4 unrelated thrombophilic patients with early and recurrent thrombosis that had normal antithrombin activity. In one case, the mutation was identified by whole genome sequencing, while in the 3 remaining cases, the mutation was identified by sequencing SERPINC1 based on a single functional positive finding supporting deficiency. The 2 variants shared a common functional defect, an impaired or null N-glycosylation of Asn224 according to a eukaryotic expression model. Carriers had normal anti-FXa or anti-FIIa activities but impaired anti-FVIIa activity and a detectable loss of inhibitory function when incubating the plasma for 1 hour at 41°C. Moreover, the β glycoform of the variants, lacking 2 N-glycans, had reduced secretion, increased heparin affinity, no inhibitory activity, and a potential dominant–negative effect. These results explain the increased thrombin generation observed in carriers. Mutation experiments reflected the role that Lysine residues close to the N-glycosylation sequon have in impairing the efficacy of N-glycosylation. Our study shows new elements involved in the regulation of N-glycosylation, a key posttranslational modification that, according to our results, affects folding, secretion, and function, providing new evidence of the pathogenic consequence of an incorrect N-glycosylation of antithrombin. This study supports that antithrombin deficiency is underestimated and encourages the development of new functional and genetic tests to diagnose this severe thrombophilia.

Pre-operative Hemostatic Status in Dogs Undergoing Splenectomy for Splenic Masses

Portal system thrombosis is a rare but potentially fatal complication of splenectomy in dogs. The mechanism behind development of post-operative portal system thrombosis is unclear but may include alterations of portal blood flow following surgery, acquired hypercoagulability and endothelial dysfunction. The aim of the study was to evaluate hemostatic biomarkers in hemodynamically stable (heart rate <130 beats/min, blood lactate < 2.5 mMol/L) and non-anemic (hematocrit >35%) dogs prior to splenectomy for splenic masses. Our hypothesis was that this population of stable dogs would have pre-existing laboratory evidence of hypercoagulability unrelated to shock, bleeding, anemia, or other pre-operative comorbidities. Pre-operatively, abdominal ultrasonography was performed and blood was collected for platelet enumeration, prothrombin time (PT), activated partial thromboplastin time (aPTT), kaolin-activated thromboelastography (TEG), fibrinogen, von Willebrand factor activity (vWF:Ag), antithrombin and thrombin-antithrombin complex (TAT). Histopathological diagnosis and 30-day survival were recorded. None of the 15 enrolled dogs had pre-operative sonographic evidence of portal system thrombosis. Three of fifteen dogs were thrombocytopenic, three had thrombocytosis, three were hyperfibrinogenemic, one had low vWF:Ag, three had mild prolongations of PT and none had abnormal aPTT. Based on the TEG G value, 13/15 dogs were hypercoagulable (mean ± SD 13.5 ± 5.4 kd/s). Antithrombin deficiency was identified in 9/15 dogs (mean ± SD 68.7 ± 22.7%) with 5/9 having concurrently elevated TAT suggesting active thrombin generation. No dogs developed portal system thrombosis and all achieved 30-day survival. Pre-operative hypercoagulability was recognized commonly but its association with post-operative thrombosis remains undetermined.

Thrombotic Thrombocytopenic Purpura (ADAMTS13 [a Disintegrin and Metalloproteinase With a Thrombospondin Type 1 Motif, Member 13] Deficiency) as Cause of Recurrent Multiterritory Ischemic Strokes.

Thrombotic Thrombocytopenic Purpura (ADAMTS13 [a Disintegrin and Metalloproteinase With a Thrombospondin Type 1 Motif, Member 13] Deficiency) as Cause of Recurrent Multiterritory Ischemic Strokes.

Prevention of venous thromboembolism in pregnant women with congenital antithrombin deficiency: a retrospective study of a candidate protocol.

The best thromboprophylaxis for pregnant women with congenital antithrombin deficiency (CAD) is controversial. To clarify the effectiveness of a protocol for venous thromboembolism (VTE) prevention in pregnant women with CAD. Women at high risk of VTE were administered antithrombin concentrate and heparin after conception, whereas those at low risk of VTE were administered heparin alone until delivery. All women received antithrombin concentrate at delivery except for one who was diagnosed with CAD. Ten women had CAD, including one in the high-risk group and nine in the low-risk group. No women had VTE at delivery as per the protocol for VTE prevention. Almost all women had increased antithrombin activity before delivery followed by maintenance at ≥ 70% due to antithrombin concentrate administration. VTE prophylaxis during and after delivery was successful in all women with CAD. However, one woman in the low-risk group did not receive heparin and developed VTE induced by severe hyperemesis at 9 gestational weeks, before the diagnosis of CAD. Women in the high-risk group received antithrombin concentrate after delivery but had increased D-dimer levels at postpartum. Our protocol to prevent VTE in pregnant women with CAD is safe and effective.

High Prevalence of Plasminogen Activator Inhibitor-1 4G/5G Polymorphism among Patients with Venous Thromboembolism in Kerala, India.

Venous thromboembolism (VTE) is a multifactorial clotting disorder in which inherited and environmental factors synergistically contribute to its pathogenesis. The aim of this case-control study was to analyze the prevalence of hereditary thrombophilic risk factors, provoking and non-provoking environmental risk factors in patients with VTE from Kerala, India. We have observed a low prevalence of factor V Leiden (7%), prothrombin G20210A (2%), and prothrombin G20030A (2%) mutations and a high prevalence of plasminogen activator inhibitor-1 (PAI-1) 4G/5G (52%), PAI-1 4G/4G (24%) genotypes in the VTE patients (n = 147). Deficiency of anticoagulants, antithrombin (3.4%), and protein C (4.1%) was relatively low. None of the risk factors were observed in 17% of the patients. Majority of VTE patients were younger than 50 years with a median age of 43 years. In conclusion, our results indicate a high prevalence of PAI-1 4G/5G polymorphism among the VTE patients which is in concordance with previous studies in the Asian population. The PAI-1 4G/5G polymorphism could be a potential biomarker for assessing VTE risk, particularly among the Indian population.

Molecular Dissection of Structural Variations Involved in Antithrombin Deficiency

Inherited antithrombin deficiency, the most severe form of thrombophilia, is predominantly caused by variants in SERPINC1. Few causal structural variants have been described, usually detected by multiplex ligation-dependent probe amplification or cytogenetic arrays, which only define the gain or loss and the approximate size and location. This study has done a complete dissection of the structural variants affecting SERPINC1 of 39 unrelated patients with antithrombin deficiency using multiplex ligation-dependent probe amplification, comparative genome hybridization array, long-range PCR, and whole genome nanopore sequencing. Structural variants, in all cases only affecting one allele, were deleterious and caused a severe type I deficiency. Most defects were deletions affecting exons of SERPINC1 (82.1%), but the whole cohort was heterogeneous, as tandem duplications, deletion of introns, or retrotransposon insertions were also detected. Their size was also variable, ranging from 193 bp to 8 Mb, and in 54% of the cases involved neighboring genes. All but two structural variants had repetitive elements and/or microhomologies in their breakpoints, suggesting a common mechanism of formation. This study also suggested regions recurrently involved in structural variants causing antithrombin deficiency and found three structural variants with a founder effect: the insertion of a retrotransposon, duplication of exon 6, and a 20-gene deletion. Finally, nanopore sequencing was determined to be the most appropriate method to identify and characterize all structural variants at nucleotide level, independently of their size or type.

Classic Thrombophilias and Thrombotic Risk Among Middle-Aged and Older Adults: A Population-Based Cohort Study.

BackgroundFive classic thrombophilias have been recognized: factor V Leiden (rs6025), the prothrombin G20210A variant (rs1799963), and protein C, protein S, and antithrombin deficiencies. This study aimed to determine the thrombotic risk of classic thrombophilias in a cohort of middle‐aged and older adults.Methods and ResultsFactor V Leiden, prothrombin G20210A and protein‐coding variants in the PROC (protein C), PROS1 (protein S), and SERPINC1 (antithrombin) anticoagulant genes were determined in 29 387 subjects (born 1923–1950, 60% women) who participated in the Malmö Diet and Cancer study (1991–1996). The Human Gene Mutation Database was used to define 68 disease‐causing mutations. Patients were followed up from baseline until the first event of venous thromboembolism (VTE), death, or Dec 31, 2018. Carriership (n=908, 3.1%) for disease‐causing mutations in the PROC, PROS1, and SERPINC1 genes was associated with incident VTE: Hazard ratio (HR) was 1.6 (95% CI, 1.3–1.9). Variants not in Human Gene Mutation Database were not linked to VTE (HR, 1.1; 95% CI, 0.8–1.5). Heterozygosity for rs6025 and rs1799963 was associated with incident VTE: HR, 1.8 (95% CI, 1.6–2.0) and HR, 1.6 (95% CI, 1.3–2.0), respectively. The HR for carrying 1 classical thrombophilia variant was 1.7 (95% CI, 1.6–1.9). HR was 3.9 (95% CI, 3.1–5.0) for carriers of ≥2 thrombophilia variants.ConclusionsThe 5 classic thrombophilias are associated with a dose‐graded risk of VTE in middle‐aged and older adults. Disease‐causing variants in the PROC, PROS1, and SERPINC1 genes were more common than the rs1799963 variant but the conferred genetic risk was comparable with the rs6025 and rs1799963 variants.

Epidemiology, diagnosis and management of neonatal thrombosis: a single-center cohort study.

The incidence of neonatal venous and arterial thrombosis ranges from 6.9 to 15/1000 neonatal ICU (NICU) admissions, and is likely an underestimate based on population demographics, frequency of surveillance and vascular catheterization. This retrospective study involving 234 infants reviewed the epidemiology, diagnosis, and management of neonatal thrombosis in a single, tertiary care institution over more than 10 years. The incidence of thrombosis was 25/1000 NICU admissions, with a preterm to term infant ratio of 1.5 : 1 and a slightly higher proportion of male sex (55.1%). The mean (range) gestational age and birth weight was 33.8 weeks (23-41.6) and 2360 g (512-5890). The median age (IQR) of thrombus diagnosis was 7 (3-17) days. Portal vein thrombosis was most prevalent (59.4%) compared with other sites of thrombosis. Almost three-quarter (171/234; 73.1%) of the thrombotic episodes were line-related, while infection and surgery were associated with 19.7% (46/234) and 10.7% (25/234), respectively. Twenty patients (8.3%) were screened for thrombophilia and 3 were positive; 2 for antithrombin deficiency, 1 for factor V Leiden gene mutation. Subjects were followed with imaging for 3 months with a treatment duration, mean (IQR) of 33.5 (10.8-42.5) days. Complete clot resolution was significantly higher in the anticoagulation group (48%; 17%; P = 0.03) compared with untreated patients. No group difference was noted for partial thrombus resolution (33.3%; 12.4%; P = 0.313). Anticoagulation halted thrombus progression (2.6 versus 12.4%; P = 0.025) and fewer treated patients failed to attend follow-up visits (6.5 versus 18.6%; P = 0.022). Well designed, multicenter prospective studies with larger sample sizes are required to confirm these findings.

Potential mechanisms of resistance to current anti-thrombotic strategies in Multiple Myeloma.

Multiple Myeloma (MM) is a common haematological malignancy that is associated with a high rate of venous thromboembolism (VTE) with almost 10% of patients suffering thrombosis during their disease course. Recent studies have shown that, despite current thromboprophylaxis strategies, VTE rates in MM remain disappointingly high. The pathophysiology behind this consistently high rate of VTE is likely multifactorial. A number of factors such as anti-thrombin deficiency or raised coagulation Factor VIII levels may confer resistance to heparin in these patients, however, the optimal method of clinically evaluating this is unclear at present, though some groups have attempted its characterisation with thrombin generation testing (TGT). In addition to testing for heparin resistance, TGT in patients with MM has shown markedly varied abnormalities in both endogenous thrombin potential and serum thrombomodulin levels. Apart from these thrombin-mediated processes, other mechanisms potentially contributing to thromboprophylaxis failure include activated protein C resistance, endothelial toxicity secondary to chemotherapy agents, tissue factor abnormalities and the effect of immunoglobulins/“M-proteins” on both the endothelium and on fibrin fibre polymerisation. It thus appears clear that there are a multitude of factors contributing to the prothrombotic milieu seen in MM and further work is necessitated to elucidate which factors may directly affect and inhibit response to anticoagulation and which factors are contributing in a broader fashion to the hypercoagulability phenotype observed in these patients so that effective thromboprophylaxis strategies can be employed.

Clinical guidance for the peripartum management of patients with hereditary thrombophilia

Hereditary thrombophilia is a condition in which individuals are susceptible to the formation of thrombi due to a hereditary deficiency in the anticoagulant factors antithrombin (AT), protein C, or protein S. The recommendations for peripartum management are as follows: 1) For women with acute venous thromboembolism (VTE) during pregnancy, anticoagulant therapy with a therapeutic dose of unfractionated heparin (UFH) is recommended; 2) For women with a history of VTE, a prophylactic dose of UFH is suggested during pregnancy; 3) For those with AT deficiency, supplementation with an AT preparation in addition to UFH is suggested; 4) For women with no history of VTE, anticoagulant therapy during pregnancy is considered for each thrombophilia type; 5) When anticoagulant therapy consisting of a prophylactic dose of UFH is administered during pregnancy, injection is discontinued with the onset of labor pains in cases of vaginal delivery and 6 hours before the start of delivery in cases of planned delivery or cesarean section; 6) In cases of AT deficiency, regardless of the thrombophilia type, supplementation with AT before and after delivery is suggested; 7) For women with thrombophilia and a history of VTE and for those who receive anticoagulant therapy during pregnancy, postpartum anticoagulant therapy is recommended.

先天性アンチトロンビン欠損症による再発性脳静脈洞血栓症に対して血管内治療を行った1例

先天性アンチトロンビン欠損症による再発性脳静脈洞血栓症に対して血管内治療を行った1例

Generation of a human iPSC line ZZUNEUi014-A from a patient with antithrombin deficiency caused by mutation in SERPINC1 gene

Inherited antithrombin (AT) deficiency is an autosomal dominant disorder associated with SERPINC1 mutations. In this study, we generated a human induced pluripotent stem cell (iPSC) line ZZUNEUi014-A from peripheral blood mononuclear cells of a female AT deficiency patient with the p. W27X (c. 80G > A) mutation in SERPINC1. This cell line expressed pluripotency markers, showed normal female karyotype and could differentiate into all three germ layers in vitro.

Inherited antithrombin deficiency in pregnancy

Inherited AntiThrombin Deficiency (ATD) is a rare and high-risk thrombophilia. It is associated with a high risk of venous thromboembolism, thrombosis, and the risk is escalated further in the prothrombotic state of pregnancy. Due to the thrombotic tendency it is also associated with placental dysfunction due to placental thrombosis. Untreated mothers with ATD have increased rates of second and third trimester loss, pre-eclampsia & eclampsia, placental abruption, and intra-uterine growth restriction resulting in small for gestational age babies.We have conducted a comprehensive review of the literature and guidelines & summarise the role of antithrombin, how to test for it, the evidence for its role in thrombosis and obstetric complications and how best to manage this. We also aim to present what we believe is best practise for managing ATD during pregnancy and therefore provide a much needed practical guide.Managing these women during pregnancy is designed to reduce their risk of thrombosis and late obstetric complications. Due to the rarity of the condition and the ethical difficulties surrounding clinical trials in pregnant women no randomised controlled trials or large observational studies have been conducted in this area; evidence is limited to small cohort studies, which are usually retrospective. Definitions such as ‘miscarriage’ and ‘fetal loss’ are also discordant between studies and associations which makes data comparison difficult. Thus there is limited guidance on the management of ATD in pregnancy. We recommend the use of low molecular weight heparin (LMWH) during pregnancy with regular anti- Xa monitoring to ensure that women receive adequate antithrombotic therapy. Due to the efficacy of LMWH working through potentiation of antithrombin, in those with ATD, high levels of LMWH are usually required. We discuss the use of antithrombin concentrates at times where the use of LMWH is contraindicated, such as during delivery.Emerging evidence suggests that the type of antithrombin deficiency is important in risk stratification along with the individual's own thrombotic risk factors, thrombosis history and family history.