Search Results (3)

Globally, intron 22 inversions (Inv22s) of the factor VIII gene (F8) are the most frequent pathogenic variants and account for 45–50% of severe hemophilia A (SHA) cases, while intron 1 inversion (Inv1) explains 1–5% of SHA cases. The detection of both inversions by an inverse shifting-polymerase chain reaction (IS-PCR) is the first choice worldwide for the diagnosis of patients and carriers of SHA. To improve its sensitivity and reproducibility in the visualization of PCR products, we approached the IS-PCR with fluorescent capillary electrophoresis instead of agarose electrophoresis. Based on the original protocol, we modified two primers by 5’-end labeling with FAM™ fluorescent dye for the detection of the PCR products by capillary electrophoresis. Additionally, the “fast enzymes” BclI and T4-Ligase were incorporated for work saving in the genomic digestion and ligation reactions, respectively. Once we accomplished the standardization and verified the reproducibility of the modified IS-PCR method, we applied it for the diagnosis of a cohort of SHA patients and carriers. The modified IS-PCR by fluorescent capillary electrophoresis for PCR product detection is more sensitive than agarose electrophoresis. The method was also improved by using the new rapid enzymes to save time in the whole process. Full article

Background and Objectives: Despite the vast heterogeneity in the genetic defects causing hemophilia A (HA), large intron inversions represent a major cause of disease, accounting for almost half of the cases of severe HA worldwide. We investigated the intron 22 and intron 1 inversion status in a cohort of Romanian unrelated patients with severe HA. Moreover, we evaluated the role of these inversions as relative risk factors in inhibitor occurrence. Materials and Methods: Inverse shifting—a polymerase chain reaction method was used to detect the presence of intron 22 and intron 1 inversions in 156 Romanian patients with HA. Results: Intron inversion 22 was found in 41.7% of the patients, while intron 1 inversion was detected in 3.2% of the patients. Overall, large intron inversions represented the molecular defect in 44.9% of the studied patients. Our findings are in accord with previously published reports from Eastern Europe countries and with other international studies. The risk of inhibitor development was higher in patients with inversion 1 compared to the patients with HA without any inversion detected. Conclusions: The current study demonstrates the major causative role of large intron inversions in severe HA in Romanian patients. Moreover, our study confirms the contribution of intron 1 inversion in inhibitor development. Full article

Hemophilia A is an X-linked bleeding disorder caused by mutations in the FVIII gene. Genetic factors have been shown to be a risk factor for the development of inhibitors. We aimed to identify the specific variations of the FVIII gene of patients with hemophilia A with inhibitors and their association with the inhibitor titer. Methods: Cross-sectional descriptive study. We included 12 Colombian patients from a health care provider, “Integral Solutions SD”, who underwent analysis of genetic material (DNA), which was reported by the Molecular Hemostasis Laboratory in Bonn, Germany. Results: All of these patients were diagnosed with severe hemophilia A with inhibitors; ages ranged between 6 and 48 years, with a median age of 13.5 years. Molecular analysis showed the inversion of intron 22 in six patients (50.0%), a small duplication in two patients (16.7%), the inversion of intron 1 in one patient (8.3%), a large deletion (8.3%), a nonsense mutation (8.3%) and a splice-site (8.3%), findings similar to those of other studies. A total of 58.3% of the patients presented inversion mutations with a high risk of developing inhibitors A total of 83.3% of the evaluated patients presented null mutations; however the presence of high inhibitor titers was 66.7%. The most frequent mutation was the inversion intron 22. Knowing the type of mutation and its association as a risk factor for generating inhibitors invites us to delve into other outcomes such as residual values of coagulation FVIII as well as its impact on the half-life of the exogenous factor applied in prophylaxis. Full article