Analysis of PROC and PROS1 single nucleotide polymorphisms in a thrombophilia family

Antithrombin, Protein C, and Protein S: Genome and Transcriptome-Wide Association Studies Identify 7 Novel Loci Regulating Plasma Levels

BACKGROUND

Antithrombin, PC (protein C), and PS (protein S) are circulating natural anticoagulant proteins that regulate hemostasis and of which partial deficiencies are causes of venous thromboembolism. Previous genetic association studies involving antithrombin, PC, and PS were limited by modest sample sizes or by being restricted to candidate genes. In the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium, we meta-analyzed across ancestries the results from 10 genome-wide association studies of plasma levels of antithrombin, PC, PS free, and PS total.

METHODS

Study participants were of European and African ancestries, and genotype data were imputed to TOPMed, a dense multiancestry reference panel. Each of the 10 studies conducted a genome-wide association studies for each phenotype and summary results were meta-analyzed, stratified by ancestry. Analysis of antithrombin included 25 243 European ancestry and 2688 African ancestry participants, PC analysis included 16 597 European ancestry and 2688 African ancestry participants, PSF and PST analysis included 4113 and 6409 European ancestry participants. We also conducted transcriptome-wide association analyses and multiphenotype analysis to discover additional associations. Novel genome-wide association studies and transcriptome-wide association analyses findings were validated by in vitro functional experiments. Mendelian randomization was performed to assess the causal relationship between these proteins and cardiovascular outcomes.

RESULTS

Genome-wide association studies meta-analyses identified 4 newly associated loci: 3 with antithrombin levels (GCKR, BAZ1B, and HP-TXNL4B) and 1 with PS levels (ORM1-ORM2). transcriptome-wide association analyses identified 3 newly associated genes: 1 with antithrombin level (FCGRT), 1 with PC (GOLM2), and 1 with PS (MYL7). In addition, we replicated 7 independent loci reported in previous studies. Functional experiments provided evidence for the involvement of GCKR, SNX17, and HP genes in antithrombin regulation.

CONCLUSIONS

The use of larger sample sizes, diverse populations, and a denser imputation reference panel allowed the detection of 7 novel genomic loci associated with plasma antithrombin, PC, and PS levels.

A case of polycystic ovary syndrome with inevitable miscarriage and multi-site venous thrombosis caused by hereditary protein C deficiency

BACKGROUND

Polycystic ovarian syndrome (PCOS) affects up to 18% of reproductive-aged women and raises the risk of venous thromboembolic disease (VTE), due to metabolic features and an apparent fibrinolytic state. Recent studies have shown an increased risk of VTE (1.5- to 2-fold) in patients with PCOS as compared to those without PCOS. Mutations in the Protein C (PC) gene (PROC) lead to deficiency or dysfunction of the protein, Protein C deficiency is the main clotting physiological inhibitor of protein C cofactors, and is a risk factor for venous thrombosis, which can cause a variety of events, including miscarriage. This case report proposes a correlation between PCOS, protein C deficiency, venous thrombosis and inevitable miscarriage.

CASE PRESENTATION

A 33-year-old Chinese woman was diagnosed with Polycystic Ovary Syndrome (PCOS) in 2015. During the course of treatment, she took ethinylestradiol and cyproterone acetate tablets for more than one year. In 2016, she was sent to a hospital for emergency care due to explosive thrombosis (thrombosis in multiple parts of the body and pulmonary thrombosis). In 2020, the patient became pregnant via natural means and came to our hospital for treatment. During the second trimester, she experienced an inevitable miscarriage. High-throughput sequencing (NGS) of peripheral blood lymphocytes revealed that the patient had a protein C deficiency resulting from a heterozygous mutation deletion of 572_574 in exon 7.

CONCLUSION

PC deficiency in conjunction with PCOS and the concomitant use of oral contraceptive (COC) would increase the risk of VTE, especially in the early stages of COC use.

A botanical medicine dragon's blood exhibited clinical antithrombosis efficacy similar to low molecular weight heparin

Deep vein thrombosis (DVT) is a common complication following traumatic fracture with a 0.5%-1% annual incidence. Low molecular weight heparin (LMWH) is the most commonly used anticoagulation drug for DVT prevention, but treatment with LMWH is invasive. Our aim is to compare the antithrombotic effect of dragon's blood, an oral botanical anticoagulant medicine approved by the Chinese FDA, with LMWH in patients undergoing hip fracture surgery and to explore the molecular mechanisms of anticoagulation treatment. Our study recruited patients and divided them into LMWH and dragon's blood treatment group. Coagulation index tests, Doppler ultrasound and mRNA sequencing were performed before and after anticoagulation therapy. There was no significant difference in postoperative DVT incidence between the two groups (23.1% versus 15.4%, P=0.694). D-dimer (D-D) and fibrinogen degradation product (FDP) showed significant reductions in both groups after anticoagulation treatments. We identified SLC4A1, PROS1, PRKAR2B and seven other genes as being differentially expressed during anticoagulation therapy in both groups. Genes correlated with coagulation indexes were also identified. Dragon's blood and LMWH showed similar effects on DVT and produced similar gene expression changes in patients undergoing hip fracture surgery, indicating that dragon's blood is a more convenient antithrombosis medicine (oral) than LMWH (hypodermic injection).

The genetics of venous thromboembolism: a systematic review of thrombophilia families

Genetic risk factors are important for the occurrence and prognosis of venous thromboembolism (VTE). The studies of thrombophilia families are important for dissecting the genetic background of the thrombotic disease. We conducted the systematic review of all published family-based studies on VTE genetics across all racial groups through PubMed and Embase prior to 13th April 2020. This systematic review of 287 families (including 225 Caucasian families, 52 East Asian families, and families of other ethnicities) revealed a total of 21 different genes; the five most reported mutated genes were F5 (88/287, 30.7%), SERPINC1 (67/287, 23.3%), PROC (65/287, 22.6%), F2 (40/287, 13.9%) and PROS1 (48/287, 16.7%). For Caucasian families, F5 mutations were most frequently reported at 37.8% (85/225), while PROS1 mutations were most frequently reported, at 40.4% (21/52), for East Asian families (Chinese, Japanese and Korean). Factor V Leiden was reported more frequently in Caucasians than in East Asians. Missense mutations were reported frequently in the SERPINC1, PROC and PROS1 genes. In conclusion, our study found the most likely mutated genes associated with VTE among different ethnic groups and provided indications for VTE genetic testing and research in the future.

A survey of precision diagnosis and management capacity of pulmonary embolism in 90 hospitals of China

OBJECTIVE

To conduct a survey of diagnostic facility and therapeutic capability of Pulmonary thromboembolism (PE) in 90 hospitals throughout China.

METHOD

It was a cross-sectional study among the participating hospitals of the National Key Research & Development Program of China-the Precision Research of Standardized Management and Application of Pulmonary Thromboembolism to obtain the equipment and application of radiological facility to diagnose PE, laboratory tests for thrombophilia, coagulation function and the availability of anticoagulants and thrombolysis agents.

RESULTS

CT pulmonary arteriography is capable in all 90 hospitals, 71.11% of the hospitals could perform ventilation/perfusion scintigraphy, 24.44% of the hospitals do not routinely perform right heart evaluation by echocardiography. Protein C and protein S activity can be detected in half of the hospitals and warfarin pharmacogenomics tests can be conducted in 40 hospitals. Immune turbidimetry was used as the detection method of D-dimer in 72.37% hospitals. About 81.11% of participating hospitals were equipped with new novel oral anticoagulants, all of which were equipped with Rivaroxaban.

CONCLUSION

The hospitals are capable for standardized diagnosis and management PE, while the capability of precise stratification, coagulation function tests, thrombophilia screening and pharmacogenomics requires further improvement.