Gavrilova, Ralitza H.

Importance Friedreich ataxia (FA), a fatal, autosomal recessive disorder caused by pathogenic variants in the frataxin ( FXN ) gene, is characterized by progressive neurologic and cardiac disease, with cardiac disease being the major cause of death. Preclinical studies have demonstrated that systemic administration of AAVrh.10hFXN, an rh.10 serotype cardiotropic adenoassociated virus (AAV) vector expressing the normal human FXN coding sequence, reverses the cardiomyopathy in FXN-deficient mice. Objective To assess the safety and preliminary efficacy of administration of AAVrh.10hFXN to adults with FA cardiomyopathy. Design, Setting, and Participants This nonrandomized clinical trial evaluates the pooled data of 2 independent, open-label, dose-escalation trials that used the same gene therapy vector and similar clinical protocols among patients with FA cardiomyopathy at academic medical centers. Data were collected from February 22, 2022, to October 4, 2025, for trial 1 and from February 14, 2023, to September 10, 2025, for trial 2 and analyzed together from November 5, 2025, to March 12, 2026. Intervention AAVrh.10hFXN, administered intravenously in 3 dose cohorts (1.8 × 10 11 , 5.6 × 10 11 , and 1.2 × 10 12 vector genomes per kilogram of body weight). Main Outcomes and Measures In addition to safety as the primary outcome, multiple parameters of exploratory end points were assessed, including cardiac biopsy levels of FXN protein, cardiac magnetic resonance imaging–derived left ventricular mass index (LVMI), and serum high-sensitivity (hs) troponin I. Results Seventeen patients with FA cardiomyopathy (mean [SD] age, 25 [6] years; 11 [65%] female) were followed up for a mean (SD) of 20 (8) months. There were 4 serious adverse events, 3 possibly related to prednisone immunosuppression and 1 possibly vector-related myocarditis 12 months after therapy, all of which resolved. Other adverse events were transient, nonserious, or not treatment related. In all 8 patients with cardiac biopsy 3 months after therapy, there were higher levels of cardiac FXN (dose cohort 1, 20%; cohort 2, 81%; cohort 3, 123%). After therapy, LVMI was lower by at least 10% in 9 patients and stabilized in 8 patients. Excluding the patient with myocarditis, posttherapy values of serum hs troponin I were lower by at least 10% in 15 patients and higher by at least 10% in 2 patients. Conclusions and Relevance Findings of this nonrandomized clinical trial suggest that intravenous administration of AAVrh.10hFXN was well tolerated and may be a potential treatment for FA cardiomyopathy, as evidenced by preliminary improvement in exploratory efficacy end points. Trial Registration ClinicalTrials.gov Identifiers: NCT05302271 and NCT05445323

AbstractBackgroundAs new anti‐amyloid immunotherapies emerge for Alzheimer’s disease (AD), it is clear that early diagnosis of AD pathology is crucial for treatment success. This can be challenging in atypical presentations of AD and, together with our reliance on CSF or PET scans, can, at times, lead to delayed diagnosis. Here, we further explore the possible role of plasma tau phosphorylated at threonine 217 (P‐tau217) for the detection of primary AD or AD co‐pathology when frontotemporal dementia spectrum disorders are the main clinical presentation.MethodParticipants were recruited through ALLFTD, a North American multisite research consortium for the longitudinal assessment of frontotemporal lobar degeneration. After excluding cases with known FTD‐causing mutations, 573 participants with sporadic disease, mild cognitive/behavioral impairment, or healthy familial controls evaluated between 2014 and 2023 were included in this analysis (45.8% female, median age 66 years). 39 of those cases underwent neuropathological evaluation. Plasma P‐tau217 was measured with the Eli Lilly electrochemiluminescence‐based assay. P‐tau217 concentrations were compared by phenotype, disease severity, genotype, and, when available, neuropathological diagnosis with non‐parametric tests. Its diagnostic performance was tested with ROC curves. Associations between plasma P‐tau217 concentrations and clinical scales of global cognition, memory, executive function, motor function, and social cognition with linear regressions and non‐parametric tests.ResultPlasma P‐tau217 concentrations were higher in logopenic variant primary progressive aphasia (lvPPA) and amnestic dementia (AmDem), compared to participants with normal cognition or other FTD phenotypes. P‐tau217 concentrations were higher in APOE e4 carriers, compared to non‐carriers, regardless of phenotype, but were not affected by disease severity. P‐tau217 concentrations showed associations with clinical measures of global cognition, memory, and executive function, but had no associations with measures of motor function or social cognition. Plasma P‐tau217 concentrations were elevated in high and intermediate ADNC scoring, or more advanced Braak stages, even when AD was not the primary pathology.ConclusionEven when FTD is suspected, high plasma p‐tau 217 concentrations are strongly associated with underlying AD as primary pathology or contributing co‐pathology. Plasma P‐tau217 could be a tool to support the development of disease‐modifying therapies for atypical Alzheimer’s disease presentations or for FTD cases with Alzheimer’s disease co‐pathology.

ABSTRACTNoonan syndrome (NS) is a predominantly autosomal dominant condition with various cardiac and extra‐cardiac manifestations. Although it has been linked with atrial arrhythmias, ventricular arrhythmias are extremely rare in the absence of underlying structural cardiac abnormalities. We report an instance of aborted sudden cardiac arrest in a 7‐year‐old male with a confirmed SOS1 variant and a lack of evidence to support a structural cardiac, metabolic, or infectious etiology. This is the second reported instance of sudden cardiac arrest related to ventricular fibrillation in a child with SOS1‐related NS in the absence of any structural cardiac defects. Although no definitive correlation can be ascertained from a limited existing body of knowledge surrounding SOS1 and ventricular fibrillation unrelated to structural heart defects, it provokes the idea of an arrhythmia phenotype and future research is warranted to guide proper clinical treatment, monitoring, and management of such individuals.

Abstract Intracellular trafficking involves an intricate machinery of motor complexes, including the dynein complex, to shuttle cargo for autophagolysosomal degradation. Deficiency in dynein axonemal chains, as well as cytoplasmic light and intermediate chains, have been linked with ciliary dyskinesia and skeletal dysplasia. The cytoplasmic dynein 1 heavy chain protein (DYNC1H1) serves as a core complex for retrograde trafficking in neuronal axons. Dominant pathogenic variants in DYNC1H1 have been previously implicated in peripheral neuromuscular disorders (NMD) and neurodevelopmental disorders (NDD). As heavy-chain dynein is ubiquitously expressed, the apparent selectivity of heavy chain dyneinopathy for motor neuronal phenotypes remains currently unaccounted for. Here, we aimed to evaluate the full DYNC1H1-related clinical, molecular and imaging spectrum, including multisystem features and novel phenotypes presenting throughout life. We identified 47 cases from 43 families with pathogenic heterozygous variants in DYNC1H1 (aged 0–59 years) and collected phenotypic data via a comprehensive standardized survey and clinical follow-up appointments. Most patients presented with divergent and previously unrecognized neurological and multisystem features, leading to significant delays in genetic testing and establishing the correct diagnosis. Neurological phenotypes include novel autonomic features, previously rarely described behavioral disorders, movement disorders and periventricular lesions. Sensory neuropathy was identified in nine patients (median age of onset 10.6 years), of which five were only diagnosed after the second decade of life, and three had a progressive age-dependent sensory neuropathy. Novel multisystem features included primary immunodeficiency, bilateral sensorineural hearing loss, organ anomalies and skeletal manifestations, resembling the phenotypic spectrum of other dyneinopathies. We also identified an age-dependent biphasic disease course with developmental regression in the first decade and, following a period of stability, neurodegenerative progression after the second decade of life. Of note, we observed several cases in whom neurodegeneration appeared to be prompted by intercurrent systemic infections with double-stranded DNA viruses (Herpesviridae) or single-stranded RNA viruses (Ross River fever, SARS-CoV-2). Moreover, the disease course appeared to be exacerbated by viral infections regardless of age and/or severity of neurodevelopmental disorder manifestations, indicating a role of dynein in anti-viral immunity and neuronal health. In summary, our findings expand the clinical, imaging and molecular spectrum of pathogenic DYNC1H1 variants beyond motor neuropathy disorders and suggest a life-long continuum and age-related progression due to deficient intracellular trafficking. This study will facilitate early diagnosis and improve counselling and health surveillance of affected patients.