Molecular spectrum of inherited FVII deficiency in North India revealed a recurrent variant with a founder effect.

INTRODUCTION: Inherited Factor VII (FVII) deficiency is commonest among the rare bleeding disorders. A small number of patients present in infancy with severe bleeding, and many may remain asymptomatic but detected before surgery/invasive procedures. Genetic testing may be helpful in predictive testing/prenatal diagnosis in severe cases. AIM: Characterisation of clinical and genotypic spectrum of patients with inherited FVII deficiency. METHODS: Retro-prospectively, 35 cases with prolonged prothrombin time and FVII activity (FVII:C) <50 IU/dl were subjected to targeted resequencing. After in-silico analysis, variant/s were validated by Sanger sequencing in index cases and family members. Haplotype analysis was done for F7 polymorphisms. RESULTS: Severe FVII deficiency was found in 50% of patients (FVII:C ≤1 IU/dl), and 42.9% were asymptomatic. Clinical severity assessment revealed 17% severe, 17% moderate and 22.9% patients with mild bleeds. FVII levels ranged from .3 to 38 IU/dl. Molecular analysis revealed variants in 30/35 cases, of which 17 were homozygous, 10 were compound heterozygous and 3 were heterozygous. Twelve genetic variants were identified, one promoter variant c.-30A>C; seven missense (c.215C>G, c.244T>C, c.253G>C, c.904G>A, c.961C>T, c.1109G>T, c.1211G>A), two deletions (c.21delG, c.868_870delATC), and one each of nonsense c.634C>T and splice-site variant c.316+1G>A. Recurrent variants c.1109G>T and c.215C>G were found in 17 and 8 cases, 12 of the former cases were homozygous. They had the same haplotype, indicating the founder effect in North Indians. CONCLUSION: This is the largest cohort of FVII genotyping from India, confirming heterogeneity in terms of clinical manifestations, FVII activity and zygosity of the variants with a limited genotypic phenotypic correlation.

Plasminogen Activator Inhibitor-1 4G/5G Promoter Polymorphism in Indian Patients with Deep Vein Thrombosis.

A single guanosine deletion/insertion (4G/5G) polymorphism in the promoter region of plasminogen activator inhibitor-1 (PAI-1) gene encoding PAI-1 protein has been investigated in deep vein thrombosis (DVT) patients. The association between PAI-1 4G/5G polymorphism and increased risk of DVT has been reported in some studies, while others have reported a lack of association. The present study aimed to investigate if the PAI-1 4G/5G polymorphism is associated with an increased risk of DVT in the Indian population and to assess its association with thrombophilic risk factors. Fifty-two adult patients with a history of chronic or recurrent DVT and 52 healthy adult controls were genotyped for PAI-1 4G/5G polymorphism. Plasma levels of PAI-1 and other thrombophilic risk factors were also measured. PAI-1 4G/5G polymorphism was not significantly associated with an increased risk of DVT. Protein C deficiency was significantly associated with the 4G/4G genotype. Patients with the 4G/4G genotype had significantly reduced PAI-1 levels as compared to the controls. PAI-1 4G/5G polymorphism did not significantly contribute to an increased risk of DVT in the Indian population. However, in the presence of thrombophilic risk factor abnormalities, the risk of DVT is increased in individuals with the 4G/4G genotype in the Indian cohort. Supplementary Information: The online version contains supplementary material available at 10.1007/s12288-023-01660-3.

Prothrombin G20210A Mutation is Rare but not Absent Among North Indian Patients with Thromboembolic Events.

Traditionally considered to be absent in India, prothrombin gene G20210A (NM_000506.5(F2): c.*97G > A) mutation (PGM) has recently been reported in few Indian patients. We aimed to assess the prevalence of PGM in patients with thromboembolic events from north India region. The thrombophilia workup comprising Protein C, Protein S, Antithrombin functional activity, lupus anticoagulant and anti-ACA and anti-ß2GP1 antibodies were performed in coagulation analyzer (ACLTOP-500, Instrumentation Laboratory, USA) and automated chemiluminescent assay analyzer (ACUSTAR, IL) respectively. PCR-RFLP was used to perform PGM and FVL mutation. Out of 509 patients, DVT and CVT/CSVT were identified in 208 and 250 patients respectively. A total of 42 (8.2%) cases showed inherited thrombophilia and 11 (2.1%) acquired thrombophilia. Among the inherited defects, the most common was FVL mutation 31 (6%) The PGM was seen in only 2/509 (0.3%) patients. The prevalence of PGM in North Indian patients with DVT, stroke and CVT is 0.41% (2/509). Although PGM is rare in this population, its presence emphasizes its association with these conditions. However, the role of PGM testing remains debatable due to its scarcity among North Indians. Supplementary Information: The online version contains supplementary material available at 10.1007/s12288-024-01741-x.

Assessment of fibrinolytic markers in patients with deep vein thrombosis.

The association of the fibrinolytic markers with deep vein thrombosis (DVT) is still a matter of debate. The present study aimed to investigate the association between fibrinolytic markers and DVT. This observational study recruited 52 adult cases with lower limb DVT and 52 healthy adult volunteers as controls. The quantitative determination of plasminogen activator inhibitor-1 (PAI-1), plasminogen, thrombin activable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (tPA) and α2-antiplasmin (α2-AP) was performed by ELISA. TAFI, plasminogen and t-PA were significantly higher in cases than controls and PAI-1 was significantly lower in cases than controls. In addition, TAFI, plasminogen and t-PA levels were significantly increased in unprovoked and idiopathic DVT cases than controls. The present study suggests that the fibrinolytic markers tested in patients with a remote history of DVT are different than in individuals with no history of DVT and, with further study, may prove useful as screening assays for DVT risk.

Next-Generation Sequencing Based Approach to Identify Underlying Genetic Defects of Glanzmann Thrombasthenia.

Glanzmann thrombasthenia (GT) is an autosomal recessive platelet function disorder characterized by mucocutaneous bleeding as the most common clinical phenotype. Patients with GT have normal platelet counts, platelet morphology but reduced platelet aggregation in response to various agonists. Homozygosity or compound heterozygosity for variants in the ITGA2B/ITGB3 genes is the genetic basis for GT. Establishing a molecular diagnosis is definitive and is important for predictive testing. Using multi-gene panels is an accurate, faster, and cost-effective mode as compared to Sanger sequencing in large genes. We used a targeted resequencing based approach to identify pathogenic variants in eight cases in seven families. These variants were validated using Sanger sequencing in patients as well as family members and were predicted probably pathogenic using in-silico prediction tools. The variants include three missense (3/7 = 43%) (ITGA2B:c.1028 T > C, ITGA2B:c.1186G > A, ITGB3:c.1388G > C), two deletions (ITGA2B:c.559delG, ITGA2B:c.3092delT), one duplication (ITGA2B:c.1424_1427dupAGGT) and nonsense variant (ITGA2B:c.2578C > T, p.Gln860Ter). Except for one case which was compound heterozygous, the rest of the cases were homozygous. We found two novel variants that are reported for the first time in GT. The targeted resequencing based approach revealed varied genetic variants in North Indian patients, including two novels ones. The high yield of our panel indicates its suitability for usage in larger cohorts for the genetic diagnosis of GT patients. This approach is cost-effective and less cumbersome as compared to Sanger sequencing for these large size genes with multiple exons. The information so obtained is helpful in prenatal testing, carrier analysis, and genetic counseling.