Congenital Combined Bleeding Disorders, a Comprehensive Study of a Large Number of Iranian Patients

Clinical, Laboratory, and Molecular Aspects of Factor VII Deficiency

Congenital factor VII (FVII) deficiency, the most frequent among the recessively inherited disorders of blood coagulation, is characterized by a wide range of symptoms, from mild mucosal bleeds to life-threatening intracranial hemorrhage. Complete FVII deficiency may cause perinatal lethality. Clinically relevant thresholds of plasma levels are still uncertain, and modest differences in low FVII levels are associated with large differences in clinical phenotypes. Activated FVII (FVIIa) expresses its physiological protease activity only in a complex with tissue factor (TF), which triggers clotting at a very low concentration. Knowledge of the FVIIa-TF complex helps to interpret the clinical findings associated with low FVII activity as compared with other rare bleeding disorders and permits effective management, including prophylaxis, with recombinant FVIIa, which, however, displays a short half-life. Newly devised substitutive and nonsubstitutive treatments, characterized by extended half-life properties, may further improve the quality of life of patients. Genetic diagnosis has been performed in thousands of patients with FVII deficiency, and among the heterogeneous F7 mutations, mostly missense changes, several recurrent variants show geographical distribution and identity by descent. In the general population, common F7 polymorphisms explain a large proportion of FVII level variance in plasma through FVII-lowering effects. Their combination with pathogenic variants may impact on the frequent detection of FVII coagulant levels lower than normal, as well as on mild bleeding conditions. In the twenties of this century, 70 years after the first report of FVII deficiency, more than 200 studies/reports about FVII/FVII deficiency have been published, with thousands of FVII-deficient patients characterized all over the world.

Genotype-Phenotype Relationship among 785 Unrelated White Women with Inherited Congenital Factor VII Deficiency: A Three-Center Database Study

BACKGROUND

Congenital factor VII (FVII) deficiency, a rare bleeding disorder resulting from mutations in the F7 gene with autosomal recessive inheritance, exhibits clinical heterogeneity that lacks a strong correlation with FVII:C levels. The objective of this study was to discern genetic defects and assess their associations with the clinical phenotype in a substantial cohort comprising 785 white women exhibiting FVII:C levels below the age-dependent cut-off percentage.

PATIENTS AND METHODS

Individuals with verified inherited factor VII deficiency underwent i) genotyping using the Sanger method and multiplex ligation-dependent probe amplification (MLPA) to identify F7 mutations, including common polymorphic variants. Additionally, they were ii) categorized based on clinical bleeding scores (BS). Thrombophilic variants and blood groups were also determined in the study participants.

RESULTS

The probands in this study encompassed both asymptomatic individuals (referred for a laboratory investigation due to recurrent prolonged prothrombin time; n = 221) and patients who manifested mild, moderate, or severe bleeding episodes (n = 564). The spectrum of bleeding symptoms included epistaxis, gum bleeding, gastrointestinal bleeding, hematuria, postoperative bleeding, and gynecologic hemorrhage. The median ISTH bleeding score (BS) recorded within a two-year period prior to the work-up was 2 (0-17). Notably, this score was significantly higher in symptomatic women compared to their asymptomatic counterparts (3 versus 0; p < 0.001). The corresponding PBAC score before hormonal treatment stood at 225 (5-1200), exhibiting a positive correlation with the ISTH BS (rho = 0.38; p = 0.001). Blood group O was more prevalent in symptomatic women compared to asymptomatic individuals (58 versus 42%; p = 0.01). Among the 329 women (42%), known and novel mutations in the F7 gene, encompassing coding regions, exon/intron boundaries, and the promoter region, were identified, while common polymorphisms were detected in 647 subjects (95%). Logistic regression analysis, adjusted for clinical and laboratory data (including blood group, FVII activity, the presence of F7 gene mutations and/or polymorphisms, thrombophilia status, and additional factor deficiencies) revealed that older age at referral (increase per year) (odds/95% CI: 1.02/1.007-1.03), the presence of blood group O (odds/95% CI: 1.9/1.2-3.3), and the coexistence of further bleeding defects (odds/95% CI: 1.8/1.03-3.1) partially account for the differences in the clinical bleeding phenotype associated with FVII deficiency.

CONCLUSION

The clinical phenotype in individuals with FVII deficiency is impacted by factors such as age, blood group, and the concurrent presence of other bleeding defects.

Viral Vectors, Exosomes, and Vexosomes: Potential Armamentarium for Delivering CRISPR/Cas to Cancer Cells

The underlying cause of cancer is genetic disruption, so gene editing technologies, particularly CRISPR/Cas systems can be used to go against cancer. The field of gene therapy has undergone many transitions over its 40-year history. Despite its many successes, it has also suffered many failures in the battle against malignancies, causing really adverse effects instead of therapeutic outcomes. At the tip of this double-edged sword are viral and non-viral-based vectors, which have profoundly transformed the way scientists and clinicians develop therapeutic platforms. Viruses such as lentivirus, adenovirus, and adeno-associated viruses are the most common viral vectors used for delivering the CRISPR/Cas system into human cells. In addition, among non-viral vectors, exosomes, especially tumor-derived exosomes (TDEs), have proven to be quite effective at delivering this gene editing tool. The combined use of viral vectors and exosomes, called vexosomes, seems to be a solution to overcoming the obstacles of both delivery systems.

A case-control study on factor V Leiden: an independent, gender-dependent risk factor for venous thromboembolism

BACKGROUND

Activated protein C resistance (APCR) due to factor V Leiden (FVL) mutation (R506Q) is a major risk factor in patients with venous thromboembolism (VTE). The present study investigated the clinical manifestations and the risk of venous thromboembolism regarding multiple clinical, laboratory, and demographic properties in FVL patients.

MATERIAL AND METHODS

A retrospective cross-sectional analysis was conducted on a total of 288 FVL patients with VTE according to APCR. In addition, 288 VET control samples, without FVL mutation, were also randomly selected. Demographic information, clinical manifestations, family and treatment history were recorded, and specific tests including t-test, chi-square and uni- and multi-variable regression tests applied.

RESULTS

APCR was found to be 2.3 times significantly more likely in men (OR: 2.1, p < 0.05) than women. The risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) in APCR patients was 4.5 and 3.2 times more than the control group, respectively (p < 0.05). However, APCR could not be an independent risk factor for arterial thrombosis (AT) and pregnancy complications. Moreover, patients were evaluated for thrombophilia panel tests and showed significantly lower protein C and S than the control group and patients without DVT (p < 0.0001).

CONCLUSION

FVL mutation and APCR abnormality are noticeable risk factors for VTE. Screening strategies for FVL mutation in patients undergoing surgery, oral contraceptive medication, and pregnancy cannot be recommended, but a phenotypic test for activated protein C resistance should be endorsed in patients with VTE.