Deficiency of antithrombin and protein C gene in 202 Chinese venous thromboembolism patients

Unraveling the Molecular Pathogenesis of Protein C Deficiency-Associated VTE: Insights from Protein C Mutations C238G and R189W in Thai Patients

BACKGROUND

 Protein C (PC) deficiency is a well-established risk factor for thromboembolism (TE), commonly manifesting in pediatric patients. This study aimed to elucidate the pathogenic mechanisms of two novel PC mutations, C238G and R189W, identified in Thai children with both venous and arterial TE.

MATERIAL AND METHODS

 The effects of wild-type (WT), C238G, and R189W PC variants were investigated through transient transfection of HEK293T cells. PC secretion levels were measured, and immunofluorescence analysis was performed to assess intracellular localization. ER stress-related gene expression and UPR activation were evaluated. Structural analysis was conducted to explore the significance of the C238 and R189W residue in PC functionality.

RESULTS

 The C238G mutation led to a severe 95% reduction in PC secretion, while R189W showed a 30% decrease compared with WT. Immunofluorescence revealed that C238G-PC was predominantly retained in the ER, indicating protein misfolding. C238G-expressing cells exhibited significant upregulation of ER stress-related genes and UPR activation. In contrast, R189W resulted in only a modest increase in UPR gene expression, suggesting a less pronounced impact on protein folding and secretion. Structural analysis demonstrated the critical role of the C238 residue in maintaining PC's disulfide bond and overall conformation.

CONCLUSION

 This study reveals distinct molecular mechanisms by which the C238G and R189W mutations contribute to PC deficiency and increased thrombotic risk. The findings emphasize the essential role of the C238 residue in preserving PC structure and secretion, enhancing the understanding of PC deficiency-associated TE in pediatric patients.

Two cases of venous thromboembolism in siblings after splenectomy due to a novel PROC gene mutation

BACKGROUND

Venous thromboembolism(VTE)is a common multifactorial disease. Anticoagulant protein deficiency is the most usual hereditary thrombophilia in the Chinese people, which includes protein C(PC), protein S and antithrombin deficiencies.

CASE PRESENTATION

A retrospective analysis was conducted on clinical manifestations, laboratory tests, genetic information, and other relevant data of siblings diagnosed with VTE in 2020 at the Department of Pediatrics of Shenzhen Second People's Hospital. The proband, a 12-year-old female, was admitted to the hospital in December 2020 with a complaint of pain in the left lower limb for four days. The examination found that the PC activity was 53%, and B-ultrasound showed bilateral thrombosis of the great saphenous vein in the thigh segment. The proband's younger brother, a 10-year-old male, was admitted to the hospital in January 2021 due to right lower limb pain for two weeks. PC activity is 40%. B-ultrasound showed superficial venous thrombosis in the left lower limb and upper limb. Both siblings suffered from thalassemia and underwent splenectomy before recurrent thrombosis occurred. The proband's mother was asymptomatic, and her PC activity was 45%. Both cases were treated with warfarin anticoagulation, and their symptoms improved. The proband's mother was found to have a heterozygous mutation at this locus through Sanger sequencing.

CONCLUSION

Protein C deficiency should be considered for venous thromboembolism in childhood. The heterozygous mutation 1204 A > G in PROC exon 9 in this family is reported for the first time.

Thrombosis of the Vein of Trolard: An Atypical Presentation of Protein C Deficiency

Cerebral venous thrombosis refers to complete or partial occlusion of the cerebral sinus/es or the feeding cortical veins, resulting in secondary effects of vascular congestion and focal or generalized neurological deficits. One of the important causes of venous thromboembolism is inherited thrombophilia. Our case is of a 34-year-old male with no previous comorbidity who presented to the emergency department with complaints of sudden onset left-sided weakness, seizures, and loss of consciousness for one day. Thrombosis of the vein of Trolard was diagnosed based on magnetic resonance venography (MRV) film. His MRI with MRV revealed an attenuated caliber of the vein of Trolard along with abnormal signal intensity in the right fronto-parietal region and the right falcine location. He was managed with intravenous medication, including levetiracetam and topiramate. Once the diagnosis was established, he was commenced on subcutaneous Enoxaparin. Consequently, his GCS improved from 6/15 to 15/15 within the first 24 hours, and he could move his limbs on the day of discharge without any significant disability.

Congenital thrombophilia in East-Asian venous thromboembolism population: a systematic review and meta-analysis

Background

Various inherited traits contribute to the overall risk of venous thromboembolism (VTE). In addition, the epidemiology of thrombophilia in the East-Asian VTE population remains unclear; thus, we aimed to assess the proportion of hereditary thrombophilia via a meta-analysis.

Methods

Publications from PubMed, EMBASE, web of science, and Cochrane before December 30, 2022, were searched. Studies from Japan, Korea, China, Hong Kong, Taiwan, Singapore, Thailand, Vietnam, Myanmar, and Cambodia were included. Congenital thrombophilia was described as diseases including protein C (PC) deficiency, protein S (PS) deficiency, antithrombin (AT) deficiency, factor (F)V Leiden (FVL), and prothrombin G20210A mutations. Studies were selected by 2 reviewers for methodological quality analysis. A random-effects model was used for the meta-analysis, assuming that estimated effects in the different studies are not identical.

Results

Forty-four studies involving 6453 patients from 7 counties/regions were included in the meta-analysis. The prevalence of PC, PS, and AT deficiencies were 7.1%, 8.3%, and 3.8%, respectively. Among 2924 patients from 22 studies, 5 patients were carriers of FVL mutation. Among 2196 patients from 10 studies, 2 patients were carriers of prothrombin G20210A mutation in a Thailand study.

Conclusion

The prevalence of PC, PS, and AT deficiencies was relatively high, while a much lower prevalence of FVL and prothrombin G20210A mutations were identified in East-Asian patients with VTE. Our data stress the relative higher prevalence of PC, PS, and AT deficiencies for thrombophilia in the East-Asian VTE population.

Surgical treatment of traction retinal detachment associated with compound heterozygous congenital protein C deficiency

Purpose

Congenital protein C deficiency leads to a prothrombotic state that may result in potentially sight- and life-threatening thromboembolic attacks. In this report, we report two cases of infants with compound heterozygous protein C deficiency who underwent lensectomies and vitrectomies for the treatment of traction retinal detachments (TRDs).

Observations

One two-month-old and one three-month-old female neonates with leukocoria and purpura fulminans received a diagnosis of protein C deficiency and were referred to ophthalmology. In both cases, the right eye had a total retinal detachment that was considered inoperable, while the left eye had a partial TRD for which surgery was performed. Of the two operated eyes, one resulted in a total retinal detachment, while the other eye has remained stable with no retinal detachment progression three months after surgery.

Conclusions

Compound heterozygous congenital protein C deficiency may lead to the rapid development of severe TRDs with poor visual and anatomical prognoses. Early diagnosis and surgery for the treatment of partial TRDs with low disease activity may help prevent progression towards total retinal detachments in these infants.

Machine learning algorithm as a prognostic tool for venous thromboembolism in allogeneic transplant patients

As a serious complication after allogenic hematopoietic stem cell transplantation (allo-HSCT), venous thromboembolism (VTE) is significantly related to increased nonrelapse mortality. Therefore distinguishing patients at high risk of death who should receive specific therapeutic management is key to improving survival. This study aimed to establish a machine learning-based prognostic model for the identification of post-transplantation VTE patients who have a high risk of death. We retrospectively evaluated 256 consecutive VTE patients who underwent allo-HSCT at our center between 2008 and 2019. These patients were further randomly divided into (1) a derivation (80%) cohort of 205 patients and (2) a test (20%) cohort of 51 patients. The least absolute shrinkage and selection operator (LASSO) approach was used to choose the potential predictors from the primary dataset. Eight machine learning classifiers were used to produce 8 candidate models. A 10-fold cross-validation procedure was used to internally evaluate the models and to select the best-performing model for external assessment using the test cohort. In total, 256 of 7238 patients were diagnosed with VTE after transplantation. Among them, 118 patients (46.1%) had catheter-related venous thrombosis, 107 (41.8%) had isolated deep-vein thrombosis (DVT), 20 (7.8%) had isolated pulmonary embolism (PE), and 11 (4.3%) had concomitant DVT and PE. The 2-year overall survival (OS) rate of patients with VTE was 68.8%. Using LASSO regression, 8 potential features were selected from the 54 candidate variables. The best-performing algorithm based on the 10-fold cross-validation runs was a logistic regression classifier. Therefore a prognostic model named BRIDGE was then established to predict the 2-year OS rate. The areas under the curves of the BRIDGE model were 0.883, 0.871, and 0.858 for the training, validation, and test cohorts, respectively. The Hosmer-Lemeshow goodness-of-fit test showed a high agreement between the predicted and observed outcomes. Decision curve analysis indicated that VTE patients could benefit from the clinical application of the prognostic model. A BRIDGE risk score calculator for predicting the study result is available online (47.94.162.105:8080/bridge/). We established the BRIDGE model to precisely predict the risk for all-cause death in VTE patients after allo-HSCT. Identifying VTE patients who have a high risk of death can help physicians treat these patients in advance, which will improve patient survival.

Primary myelofibrosis with thrombophilia as first symptom combined with thalassemia and Gilbert syndrome: A case report

BACKGROUND

A 46-year-old Han man first had sigmoid sinus and transverse sinus venous thrombosis at the age of 42. At the age of 44, he once again developed thrombosis. Genetic testing showed heterozygous SERPINC1 mutation, bone marrow biopsy showed fibrosis grade 1 (MF-1), and JAK2 V617F mutation was positive, accompanied by UGT1A1 mutation and β-thalassemia gene mutation.

CASE SUMMARY

A 46-year-old Han man was first found to have sigmoid sinus and transverse sinus venous thrombosis at the age of 42 but had no individual or family thrombosis history, and he had been regularly taking warfarin anticoagulant therapy for a long period of time. At the age of 44, venous thrombosis reappeared in parts of the intrahepatic vein, main portal vein, splenic vein, and superior mesenteric vein, and his spleen was obviously enlarged. He had a history of jaundice for many years, and genetic testing revealed that he carried a heterozygous SERPINC1 mutation. Bone marrow biopsy showed multifocal fibrous tissue hyperplasia among trabeculae and focal fibrosis. He was positive for the JAK2 V617F mutation. At the same time, UGT1A1 and β-thalassemia gene mutations existed, and a SERPINC1 mutation and UGT1A1 mutation were both found in his parents.

CONCLUSION

The patient in this case had thrombophilia as the primary symptom, JAK2V617-positive myeloproliferative neoplasm (MPN) was the main potential cause, and hereditary AT-III deficiency may have been one of multiple secondary causes. It remains to be determined whether UGT1A1 and β-thalassemia gene mutations are related to thrombophilia. However, the clinical features of MPN in this patient were hidden, and the relevant clinical features of coexisting thalassemia and hereditary Gilbert syndrome, reported here for the first time domestically and abroad, were complicating factors, causing great difficulties for a clear diagnosis. Thus, when thrombophilia has been determined, it is necessary to screen the relevant latent problems overall. When the clinical features cannot be perfectly explained by one etiology, a relevant comprehensive examination should also be initiated from the perspective of multiple etiologies.

[Clinical phenotype and gene mutation analysis of 12 patients with hereditary protein C deficiency in different families]

Objective: To investigate the molecular pathogenesis and clinical features of unrelated 12 patients with inherited coagulation protein C (PC) deficiency in Chinese population. Methods: The PC activity (PC:A) and PC antigen (PC:Ag) were detected by chromogenic substrate and enzyme linked immunosorbent assay, respectively. The nine exons and flanking sequences of the protein C (PROC) gene were amplified by polymerase chain reaction with direct sequencing, and the suspected mutations were validated by reverse sequencing (clone sequencing for deletion mutations) . Results: The PC:A of the 12 probands decreased significantly, ranging from 18% to 55%, and the PC:Ag of the 10 probands decreased significantly. Eleven mutations were found, out of which four mutations [c.383G>A (p.Gly128Asp) , c.997G>A (p.Ala291Thr) , c.1318C>T (p.Arg398Cys) , and c.532G>C (p.Leu278Pro) ] were discovered for the first time. Six mutations were in the serine protease domain, four mutations were located in epidermal growth factor (EGF) -like domains, and one mutation was located in activation peptide. There were two deletion mutations (p.Met364Trp fsX15 and p.Lys192del) , and the rest were missense mutations. Mutations p.Phe181Val and p.Arg189Trp were identified in three unrelated families. All mutations may be inherited, and consanguineous marriages were reported in two families. Among the probands, nine cases had venous thrombosis, two cases had poor pregnancy manifestations, and one case had purpura. Conclusion: Patients with PC deficiency caused by PROC gene defects are prone to venous thrombosis, especially when there are other thrombotic factors present at the same time.

Establishment of a new protein C detection system based on chromogenic substrate assay and its clinical diagnostic value for deep vein thrombosis

Background

Deficiency of protein C (PC) affects the balance between blood coagulation and fibrinolysis in the human body. Chromogenic‐based assay is recommended as the preferred screening method for detecting PC deficiency. We established a PC detection system based on the chromogenic substrate assay.

Methods

First, a kit for the determination of PC activity in plasma was elaborately developed and its reaction parameters on XL‐3200c were explored. Then, we evaluated its performance and collected specimens to compare the test results obtained with those of the Siemens detection system. Finally, the clinical diagnostic efficacy of this detection system for deep vein thrombosis (DVT) was assessed.

Results

Optimum conditions for PC detection were 0.25–0.1 U/ml protein C activator Protac^® and 2.5–1 mM Pefachrome^®PCa5297. The composition and concentration ranges of buffer substances and stabilizers in the kit were also explored. Satisfactory results were observed in performance evaluation. The test results of the newly built detection system were highly correlated with those of the Siemens detection system (R² = 0.9771 in the control group and R² = 0.9776 in the DVT group), and Bland‐Altman plots also showed high consistency between the two detection systems. In addition, the area under the curve (AUC) of the newly built PC detection system for DVT was 0.888, indicating this system could effectively improve the diagnostic sensitivity and specificity for DVT.

Conclusion

In this study, a sensitive, wide linear range and reliable PC activity detection system were established.

Heritable Thrombophilia in Venous Thromboembolism in Northern Pakistan: A Cross-Sectional Study

BACKGROUND

Venous thromboembolism (VTE) is referred to as formation of clots in a deep vein or lodging of thrombus towards the lungs which could be fatal yet preventable. The risk of developing VTE can be increased by various factors. Where there are innumerable acquired causes, the possibility of inherited thrombophilia cannot be ignored. In view of this, we have evaluated all patients with venous thromboembolism for inherited thrombophilia.

OBJECTIVE

To evaluate the frequencies of antithrombin (AT) deficiency, protein C and S deficiencies, Factor V Leiden, and prothrombin gene mutations in patients harboring venous thromboembolism.

MATERIALS AND METHODS

A study comprising of 880 patients who were presented with manifestations of venous thromboembolism was conducted from July 2016 to June 2017. A blood sample collected from patients was screened for thrombophilia defects encompassing AT, protein C and S deficiencies, Factor V Leiden, and prothrombin gene mutations. All acquired causes of thrombosis were excluded.

RESULTS

Of 880 patients who underwent screening for thrombophilia, 182 patients demonstrated VTE history. Their age ranged from 1 to 58 years. Males constituted a predominant group. About 45 (24.7%) patients had evidence of heritable thrombophilia. Of these, 20 (10.9%) had AT deficiency, 9 (4.9%) had Factor V Leiden mutation, 6 (3.2%) had protein C deficiency, whereas protein S deficiency and prothrombin gene mutation both were found in 5 (2.7%) patients.

CONCLUSION

Our study illustrated the highest frequency of antithrombin deficiency among other investigated thrombophilia defects.

Outcomes of symptomatic venous thromboembolism after haploidentical donor hematopoietic stem cell transplantation and comparison with human leukocyte antigen-identical sibling transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is regarded as a curative therapy for majority of hematologic malignancies and some non-malignant hematologic diseases. Venous thromboembolism (VTE) has become increasingly recognized as a severe complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT).

OBJECTIVES

To show the characteristics of VTE after haploidentical donor hematopoietic stem cell transplantation (HID-HSCT) and make comparisons with matched related donor HSCT (MRD-HSCT).

PATIENTS/METHODS

A retrospective nested case-control study design was used, cases with VTE and matched controls were selected, with 3534 patients underwent HID-HSCT and 1289 underwent MRD-HSCT.

RESULTS

During follow-up, 114 patients with VTE were identified. The incidence of VTE in HID-HSCT group was similar to that of MRD-HSCT group (2.4% versus 2.3%, P = 0.92). In HID-HSCT group, VTE occurred at a median time of 92.5 days, which was earlier than MRD-HSCT group (243.5 days). For HID-HSCT, advanced disease status, cardiovascular risk factors, acute graft-versus-host disease (aGVHD), and relapse were the independent risk factors for VTE. For MRD-HSCT, cardiovascular risk factors, aGVHD, and relapse were associated with VTE. Overall survival (OS) of patients following HID-HSCT and MRD-HSCT were similar, but the OS in patients with VTE was significantly lower than patients without VTE.

CONCLUSIONS

There was no statistical difference in the incidence of VTE after HID-HSCT compared with MRD-HSCT. The development of VTE adversely impacted the OS after allo-HSCT.

A Study of Congenital Protein C Deficiency With Infancy Onset of CADASIL in a Chinese Baby

OBJECTIVE

The main objectives of this article were to study a severe congenital protein C deficiency (PCD) in a patient with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and analyze the cause of this case.

MATERIALS AND METHODS

We had recorded clinical manifestations of the patient, laboratory tests, imaging studies, and gene sequencing of the PROC gene and NOTCH3 gene to study the disease in this family. We checked the change of NOTCH3 protein by immunohistochemistry.

RESULTS

Laboratory studies of the patient had revealed that his PC activity was 3%. Magnetic resonance imaging results showed hyperintense lesions in the cerebral white matter of the patient. PROC gene and NOTCH3 gene sequencing was performed among the family members. The patient was confirmed as homozygous for the (A-G)-12 at the transcription initiation site in the promoter region of the PROC gene and heterozygous mutation of the NOTCH3 gene. Immunohistochemical results showed that NOTCH3 protein was positive in the skin vascular smooth muscle of the patient.

CONCLUSIONS

We studied a rare case of an infat boy diagnosed with both congenital PCD and CADASIL; congenital PCD was attributable to a compound that was homozygous for (A-G)-12 at the transcription initiation site in the promoter region of the PROC gene, and CADASIL was caused by missense mutation in exon 24 of NOTCH3. He was a sporadic patient with congenital PCD and CADASIL; it maybe that the deficiency of protein C led to early onset of CADASIL. The gene sequencing of PROC gene and NOTCH3 gene may have important value for fertility guidance and prenatal diagnosis.

Protein C deficiency resulting from two mutations in PROC presenting with recurrent venous thromboembolism

Hereditary protein C (PC) deficiency is an autosomal dominant disorder associated with a high risk of venous thromboembolism (VTE). Here we report a case of inherited PC deficiency associated with recurrent deep venous thrombosis. Two mutations were revealed in PROC (c.1152C>G, p.N384K and c.1207G>T, p.G403W) by genetic testing. Results from this case suggest that the inherited PC deficiency due to the PROC mutations may cause recurrent VTE. Long-term anticoagulant therapy may be appropriate for these patients with recurrent VTE and hereditary PC deficiency.

Risk indicators for venous thrombosis in first-degree relatives of patients with recurrent venous thromboembolism in Chinese

Having encountered several subjects with venous thromboembolism (VTE) in 1 family in which 1 proband has recurrent VTE (rVTE), we aimed to assess the risk of VTE in first-degree relatives, especially the children of individuals with rVTE, and to investigate the association of endothelial nitric oxide synthase (eNOS) G894T polymorphism between Chinese persons with rVTE and their offspring.We collected information about family histories and blood samples from 126 individuals with rVTE who had presented to our institute from 2003 to 2014, and 126 population-based controls and the first-degree relatives of subjects in these 2 groups. We tested blood samples for heritable thrombophilia and calculated odds ratios (ORs) and kappa coefficients.First-degree relatives of individuals with rVTE patients had a statistically significant risk of developing VTE (OR 2.62, 95% confidence interval [CI] 1.61-4.26, P < 0.001). For siblings, the OR was 2.72 (95% CI 1.56-4.73, P < .001). Moreover, for each year that the patient was older, the OR was 0.98 (95% CI 0.97-0.99, P = 0.03). One (11.2%) of the 9 individuals who had the same eNOS G894T polymorphism as their probands had a history of VTE, whereas none of the 17 relatives without the same polymorphism had developed VTE. The associations between patients and their children were statistically significant for VTE (kappa = 0.23, P < 0.001) and for eNOS G894T (kappa = 0.03, P = 0.04).In this case-controlled study, we demonstrated a higher risk of VTE among first-degree relatives of individuals with rVTE, especially in siblings of younger subjects with rVTE. We also found that eNOS G894T polymorphism may be a predictor of VTE in offspring of individuals with rVTE.