Haemophilia A (HA) is a rare congenital, recessive X-linked bleeding disorders caused by the lack or deficiency of clotting factor VIII (FVIII). Missense variants, which can alter protein structure, conformation and immunogenicity, are found in nearly all individuals with mild or moderate hemophilia A but in fewer than 20% of those with the severe form. Here, we identified a 26-year-old man with a hemizygous F8 mutation (NM_000132.4(F8):c.5399 G > A (p. Arg1800His)) through direct sequencing of all exons of the F8 gene, which is established to cause a lack of FVIII:c (%) in circulating blood and leads to moderate HA. In addition, we also provide evidence for the reduced active FVIII (FVIII:c (%)) caused by p. Arg1800His mutation. In detail, we show that p. Arg1800His mutation may activate the unfolded protein response through IRE1a-XBP1 pathway and reduce stability of FVIII. Results from co-immunoprecipitation assays showed that p. Arg1800His mutation decreases the interaction between FVIII and PDIA5. Furthermore, unbiased molecular dynamics simulations highlight the importance of Arg1800 in the interactions FVIII and von Willebrand factor. These findings demonstrate the crucial role of Arg1800 in the correct biogenesis of FVIII and shed light on molecular mechanisms through which missense mutations in FVIII contribute to the development of moderate hemophilia A.

Intracranial hemorrhage is a feared complication of hemophilia A, and recurrence may prompt evaluation beyond systemic hemostatic factors. We report an 18-year-old male with severe hemophilia A and no current inhibitors who experienced three episodes of spontaneous, strictly right-sided extra-axial intracranial hemorrhage (epidural and subdural) over four years. Each event presented with headache and vomiting without antecedent trauma and was managed conservatively with high-dose factor VIII replacement and close neurologic monitoring, resulting in complete clinical recovery and radiologic resolution. After the third ipsilateral event, repeated inhibitor testing remained negative, and systemic risk factor evaluation was unrevealing. Brain magnetic resonance angiography (MRA) demonstrated an ectatic right parietal cortical venous structure draining into the superior sagittal sinus with suspected arteriovenous shunting, raising concern for a dural arteriovenous fistula (DAVF). Digital subtraction angiography (DSA) was recommended for definitive diagnosis, but was not immediately available, and the patient is awaiting transfer. This case highlights that recurrent strictly unilateral extra-axial hemorrhage in hemophilia should prompt investigation for a focal structural or vascular etiology such as DAVF, particularly in resource-limited settings.

Gene therapy is reshaping the therapeutic paradigm in hemophilia by enabling sustained endogenous clotting factor production after a single administration. This approach moves disease management beyond lifelong replacement therapy. While clinical trials have demonstrated marked reductions in bleeding rates and treatment burden, real-world implementation has revealed emerging complexities. These include interindividual variability in transgene expression reflected by a progressive reduction in circulating FVIII or FIX activity over time, uncertainty regarding the long-term durability of expression, immune-mediated constraints, and episodes of transaminase elevation. This review addresses a critical transition point in the field: the shift from proof-of-concept efficacy toward integration of gene therapy into long-term hemophilia care. We examine determinants of therapeutic stability, host-vector immune interactions, and mechanisms underlying loss or fluctuation of expression, with emphasis on monitoring strategies and post-therapy management pathways. Immunogenic processes affecting vector transduction, hepatocellular responses, and transgene persistence are discussed alongside current approaches to immune modulation. This review uniquely focuses on post-gene therapy clinical integration rather than vector design or trial outcomes. Beyond direct factor correction, evolving therapeutic concepts targeting coagulation rebalancing and immune regulation are considered within a systems-based framework. Psychosocial adaptation and patient-reported outcomes are also explored, underscoring that therapeutic success extends beyond hemostatic control. In aggregate, these perspectives position gene therapy not as a singular curative event but as a component of an evolving, biologically integrated management strategy. Long-term follow-up translational research (LTFU) and coordinated global efforts will be essential to optimize durability, safety, and equitable access.

Hemophilia A (HA), an X-linked bleeding disorder caused by Factor VIII (F8) gene mutations, persists in the population due to sporadic cases arising from de novo mutations. This study analyzed 24 pedigrees from hemophilia registries of multiple medical centers in Taiwan to assess whether sporadic non-inversion variants (NIVs) recur in the same generation within families. Linkage analysis using intragenic and extragenic markers combined with amplification refractory mutation system-quantitative polymerase chain reaction (ARMS-qPCR) revealed that among 16 individuals inheriting the same X chromosome as the one bearing the sporadic HA-causing mutation, none carried the F8 variant. These findings strongly suggest that sporadic NIVs exhibit very low risk of recurrence. Our results provide critical information for recurrence risk assessment and counseling strategies for HA sporadic NIVs.

The kidney and the brain share similarities in terms of structure and haemodynamic regime. The aim of the study was to assess a potential correlation of vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor-1 (sFlt-1), and placental growth factor (PlGF) with biomarkers of podocyte damage, proximal tubular (PT) dysfunction, and endothelial dysfunction, as well as with cerebral vessels haemodynamic indices in neurologic asymptomatic type 2 DM patients. A cohort of 212 patients diagnosed with type 2 DM and 49 age- and gender-matched healthy controls were enrolled in the study. Parameters studied were urinary albumin/creatinine ratio (UACR), biomarkers of podocyte damage (synaptopodin, podocalyxin), PT dysfunction (kidney injury molecule-1-KIM-1, N-acetyl-β-(D)-glucosaminidase-NAG), endothelial dysfunction (P-selectin), VEGF, sFlt-1, and PlGF. The cerebrovascular hemodynamic indices evaluated were intima-media thickness (IMT) in the common carotid arteries (CCAs), the pulsatility index (PI), and the resistivity index (RI) in the internal carotid arteries (ICAs) and middle cerebral arteries (MCAs). Cerebrovascular reactivity (CVR) was assessed by the breath-holding index (BHI). In multivariable regression analysis, serum VEGF correlated directly with UACR, synaptopodin, NAG, serum P-selectin; serum sFlt-1 correlated directly with UACR, synaptopodin, podocalyxin, NAG, KIM-1; serum PlGF correlated negatively with eGFR and directly with UACR, synaptopodin, KIM-1. IMT-CCA correlated indirectly with eGFR and directly with UACR, serum P-selectin, and serum sFlt-1. The PI-ICAs correlated negatively with eGFR and positively with UACR, synaptopodin, serum P-selectin, and serum sFlt-1. The PI-MCAs correlated indirectly with eGFR and directly with synaptopodin, serum P-selectin, and serum sFlt-1. The RI-ICAs had a negative correlation with eGFR and a positive one with UACR, synaptopodin, NAG, KIM-1, urinary sFlt-1, and serum PlGF. The RI-MCAs displayed an indirect correlation with eGFR and a direct correlation with NAG, KIM-1, and serum sFlt-1. The BHT correlated directly with eGFR and negatively with serum P-selectin and serum PlGF. The study shows a significant association of VEGF, sFlt-1, and PlGF with biomarkers of podocyte injury, PT dysfunction, and endothelial dysfunction in early stages of DKD. These pro-angiogenic and anti-angiogenic factors correlated with cerebrovascular haemodynamic indices in neurologic asymptomatic type 2 DM, even in the normoalbuminuric stage of diabetic kidney disease.

Background: Pediatric liver disease is frequently associated with abnormal conventional coagulation tests; however, prothrombin time expressed as international normalized ratio (PT-INR) incompletely reflect global hemostatic balance. Thrombin generation assay (TGA) provide an integrated assessment of coagulation and may offer complementary information in children with acute liver failure (ALF) and chronic liver disease (CLD). Methods: We enrolled 61 pediatric patients with liver disease (50 CLD, 8 ALF, 3 extrahepatic portal vein obstruction EHPVO) and 51 healthy controls. Platelet-poor plasma was prepared according to international recommendations. Thrombin generation was measured using ST Genesia (STG) with normalization to reference plasma. Group comparisons were performed using non-parametric tests; correlations between PT-INR and thrombin generation parameters were assessed, and principal component analysis (PCA) was used to explore the variance structure of thrombin generation indices and conventional coagulation variables. Results: PT-INR was significantly higher in patients than controls, particularly in ALF. Bleeding events were uncommon. Compared with controls, patients showed reduced levels of fibrinogen and multiple procoagulant/anticoagulant factors (including antithrombin and protein C), with increased factor VIII. Among thrombin generation parameters, the endogenous thrombin potential (ETP) ratio differed significantly across groups (p = 0.001), while correlations between PT-INR and thrombin generation parameters were weak or absent, no significant associations were observed even at higher Pediatric/Model for End-Stage Liver Disease scores. PCA separated thrombin generation indices from PT-INR and conventional coagulation factors, suggesting complementary information. Conclusions: In pediatric liver disease, PT-INR does not reliably reflect global coagulation capacity. Thrombin generation testing provides additional, integrative information on hemostasis and may improve laboratory assessment beyond conventional tests.

T-cell-dependent bispecific antibody (TDB) is a novel therapeutic antibody considered one of the promising immunotherapies for treating brain tumors. TDB activates T cells via CD3-mediated signaling by crosslinking CD3 expressed on T cells and tumor-associated antigens expressed on cancer cells. In preclinical studies, the efficacy of TDB targeting EGFRvIII, one of tumor-associated antigens, has been validated against malignant brain tumors. Despite its therapeutic potential, the in vivo dynamics of TDB and the T cells remain poorly understood. In this chapter, we describe a method to analyze the in vivo dynamics of TDB and T cells in brain tumor-bearing mice using fluorescence imaging.