Frataxin Deficit Leads to Reduced Dynamics of Growth Cones in Dorsal Root Ganglia Neurons of Friedreich’s Ataxia YG8sR Model: A Multilinear Algebra Approach

Muñoz-Lasso DC, Mollá B, Sáenz-Gamboa JJ, Insuasty E, de la Iglesia-Vaya M, Pook MA, Pallardó FV, Palau F and Gonzalez-Cabo P (2022). Front. Mol. Neurosci. 15:912780. doi: 10.3389/fnmol.2022.912780

In summary, we have evidenced an adverse effect of the deficit of frataxin in the formation and, most importantly, the growth cones’ function in adult DRG neurons by applying both classical and novel computer-assisted analysis. As a result, we propose that frataxin deficient DRG neurons might lose the intrinsic capacity to grow and regenerate axons properly due to the dysfunctional GCs they build.

AAV-vector based gene therapy for mitochondrial disease: progress and future perspectives

Hanaford, A.R., Cho, YJ. & Nakai, H.; Orphanet J Rare Dis 17, 217 (2022). doi:10.1186/s13023-022-02324-7 

This review summarizes the preclinical findings of AAV vector-based gene replacement therapy for mitochondrial diseases including Friedreich ataxia, Leigh syndrome, Barth syndrome, ethylmalonic encephalopathy, and others.

Neuroinflammation in Friedreich’s Ataxia

Apolloni, S.; Milani, M.; D’Ambrosi, N.; Int. J. Mol. Sci. 2022, 23, 6297. doi:10.3390/ijms23116297

In this review article, we discuss evidence about the involvement of neuroinflammatory-related mechanisms in models of FRDA and provide clues for the modulation of glial-related mechanisms as a possible strategy to improve disease features.

A clinical and epidemiological prevalence study on Friedreich's Ataxia in Latium, Italy

Romano S, Bacigalupo I, Marcotulli C, Cioffi E, Bertini ES, Vasco G, Perna A, Petrucci A, Massa R, Frezza E, Romano C, Salvetti M, Ristori G, Silvestri G, Vanacore N, Casali C.; Neuroepidemiology. 2022 May. DOI: 10.1159/000525159. PMID: 35636410.

We estimated the crude and standardized prevalence of FRDA in Latium. A clinical classification (EOFA, LOFA, VLOFA) gave significant correlations. This epidemiological estimate allows to monitor a disease prevalence over time in cohort studies, and/or for developing disease registry.

Metal Ion Binding in Wild-Type and Mutated Frataxin: A Stability Study

Morante, S.; Botticelli, S.; Chiaraluce, R.; Consalvi, V.; La Penna, G.; Novak, L.; et al. (2022); Frontiers. Collection. doi:10.3389/fmolb.2022.878017

We can explain the surprising feature emerging from a detailed analysis of the XANES region of the spectrum, showing that the longer 81-210 frataxin fragment has a smaller propensity for Co2+ binding than the shorter 90-210 one. This fact is explained by the peculiar role of the N-terminal disordered tail in modulating the protein ability to interact with the metal.

Clinical Evidence for Variegated Silencing in Patients With Friedreich Ataxia

Layne N. Rodden, Christian Rummey, Yi Na Dong, David R. Lynch; Neurol Genet Jun 2022, 8 (3) e683; DOI: 10.1212/NXG.0000000000000683

In the variegated silencing model in PBMCs, the proportion of spared cells decreases with increasing GAA-TR length until it plateaus at 500 triplets, at which the maximum of both number of silenced cells and severity of FXN deficiency has been reached. If such an effect occurs in affected tissues in patients, there should be a similar ceiling effect of GAA-TR length on clinical severity. Patients with GAA-TR levels greater than this ceiling would constitute a subpopulation with relatively similar frataxin levels and potentially more homogeneous clinical features when controlling for disease duration and age. Based on the variegated silencing model described in PBMCs, we aimed to determine whether the clinical features of FRDA reach a similar ceiling in which severity of symptoms reaches a maximum and worsens minimally past a certain GAA-TR length.

Anaesthesia for a patient with Friedreich’s ataxia undergoing emergency tibia interlocking nail insertion

Ahmed Abd Elmohsen Bedewy (2022), Egyptian Journal of Anaesthesia, 38:1, 324-325, DOI: 10.1080/11101849.2022.2082789

Friedreich’s ataxia has many effects on various systems of the body especially the nervous system and the heart that makes delivery of anaesthesia such a critical situation that should be dealt with caution.

Lexeo to start phase I/II clinical trial for patients with Friedreich’s ataxia cardiomyopathy

May 26, 2022 -- Gene therapy company Lexeo Therapeutics in 2022 plans to launch a phase I/II clinical trial of its adeno-associated virus-based therapy designed to intravenously deliver a functional frataxin gene for the treatment of Friedreich’s ataxia (FA) cardiomyopathy. CEO Nolan Townsend told ScienceBoard.net at the American Society of Gene & Cell Therapy (ASGCT) 2022 annual meeting in Washington, DC that LX2006, whose investigational new drug application was recently cleared by the U.S. Food and Drug Administration, is the first disease-modifying, clinical-stage gene therapy treatment for Friedreich's ataxia and the first clinical-stage program from the company's cardiovascular gene therapy pipeline.

Reata Pharmaceuticals Announces FDA Filing Acceptance and Priority Review Designation for the NDA for Omaveloxolone for the Treatment of Patients with Friedreich’s Ataxia

May 26, 2022. PLANO, Texas--(BUSINESS WIRE)-Today announced that the U.S. Food and Drug Administration (“FDA”) has accepted for filing and granted Priority Review of its New Drug Application (“NDA”) for omaveloxolone for the treatment of patients with Friedreich’s ataxia. The FDA indicated that at this time it has not identified any potential review issues. The NDA is supported by the efficacy and safety data from the MOXIe Part 2 trial and additional supporting data from the MOXIe Part 1 and MOXIe Extension trials. Omaveloxolone received Fast Track Designation in November 2021 and Rare Pediatric Disease Designation in May 2022. The FDA grants Priority Review to medicines that may offer significant improvements in the treatment, diagnosis, or prevention of a serious condition. This Designation shortens the FDA’s review of the NDA to eight months from the time of submission, versus a standard review timeline of 12 months. The FDA has assigned a Prescription Drug User Fee Act (“PDUFA”) target action date of November 30, 2022. The FDA indicated it is currently planning to hold an advisory committee meeting to discuss the application. “We are pleased with the FDA’s decision to grant Priority Review to our NDA for omaveloxolone for the treatment of patients with Friedreich’s ataxia in the United States,” said Warren Huff, Reata’s Chief Executive Officer. “With the FDA’s acceptance of our NDA for filing, omaveloxolone is now one step closer to potentially providing a treatment option for patients with Friedreich’s ataxia, a rare, genetic, debilitating, and degenerative neuromuscular disorder with no approved therapies. We look forward to working with the FDA during the review process, and if approved, we are looking forward to a commercial launch in early 2023.”

A comprehensive Triple Repeat Primed PCR (TR-PCR) and a Long-Range PCR (LR-PCR) agarose-based assay for improved genotyping of GAA repeats in Friedreich’s Ataxia

Mohamed Jama, Rebecca L. Margraf, Ping Yu, N. Scott Reading, Pinar Bayrak-Toydemir; The Journal of Molecular Diagnostics, 2022, doi:10.1016/j.jmoldx.2022.04.008. 

A two-tier genotyping assay with an improved triple-repeat primed PCR (TR-PCR) for alleles < 200 GAA repeats (± 1-5 repeats), and an agarose gel-based, long-range PCR (LR-PCR) assay to genotype expanded alleles > 200 GAA repeats (± 50 repeats) is described. Of the 1236 DNA samples tested using TR-PCR, 31 were identified to have expanded alleles >200 repeats and were reflexed to the LR-PCR procedure for confirmation and quantification. The TR-PCR assay described here, is a diagnostic genotyping assay which reduces the need for further testing. The LR-PCR component is a confirmatory test for true homozygous and heterozygous samples with normal and expanded alleles as indicated by the TR-PCR assay. The use of this two-tier methodology offers a comprehensive evaluation to detect and genotype the smallest and largest number of GAA repeats, improving the classification of FXN alleles as normal, mutable normal, borderline and expanded alleles.