Rare-disease researchers face unique obstacles: Minoryx

29-Mar-2021 By Jenni Spinner A representative of the rare-disease specialist firm outlines the unique obstacles of orphan CNS disease research, and how professionals can overcome them.

Mapa epidemiológico transversal de las ataxias y paraparesias espásticas hereditarias en EspañaEpidemiology of ataxia and hereditary spastic paraplegia in Spain: a cross-sectional study

G. Ortega Suero, M.J. Abenza Abildúa, C. Serrano Munuera, I. Rouco Axpe, F.J. Arpa Gutiérrez, A.D. Adarmes Gómez, F.J. Rodríguez de Rivera, B. Quintans Castro, I. Posada Rodríguez, A. Vadillo Bermejo, Á. Domingo Santos, E. Blanco Vicente, I. Infante Ceberio, J. Pardo Fernández, E. Costa Arpín, C. Painous Martí, J.E. Muñoz, P. Mir Rivera, F. Montón Álvarez, L. Bataller Alberola, J. Gascón Bayarri, C. Casasnovas Pons, V. Vélez Santamaría, A. López Munain, G. Fernández García Eulate, J. Gazulla Abío, I. Sanz Gallego, L. Rojas Bartolomé, Ó. Ayo Martín, T. Segura Martín, C. González Mingot, M. Baraldés Rovira, R. Sivera Mascaró, E. Cubo Delgado, A. Echevarría Íñiguez, F. Vázquez Sánchez, M. Bártulos Iglesias, M.T. Casadevall Codina, E.M. Martínez Fernández, C. Labandeira Guerra, B. Alemany Perna, A. Carvajal Hernández, C. Fernández Moreno, M. Palacín Larroy, N. Caballol Pons, A. Ávila Rivera, F.J. Navacerrada Barrero, R. Lobato Rodríguez, M.J. Sobrido Gómez; Neurología, 2021, doi:10.1016/j.nrl.2021.01.006. 

 We conducted a cross-sectional, multicentre, retrospective, descriptive study of patients with ataxia and hereditary spastic paraplegia in Spain between March 2018 and December 2019. Mean (SD) age in our sample was 53.64 (20.51) years; 920 patients were men (50.8%) and 889 were women (49.2%). The genetic defect was unidentified in 920 patients (47.6%). A total of 1371 patients (70.9%) had ataxia and 562 (29.1%) had hereditary spastic paraplegia. Prevalence rates for ataxia and hereditary spastic paraplegia were estimated at 5.48 and 2.24 cases per 100 000 population, respectively. The most frequent type of dominant ataxia in our sample was SCA3, and the most frequent recessive ataxia was Friedreich ataxia. 

Pre-clinical left ventricular myocardial remodeling in patients with Friedreich's ataxia: A cardiac MRI study

Takazaki KAG, Quinaglia T, Venancio TD, Martinez ARM, Shah RV, Neilan TG, Jerosch-Herold M, Coelho-Filho OR, França MC Jr.; PLoS One. 2021 Mar 26;16(3):e0246633. doi: 10.1371/journal.pone.0246633. LV hypertrophy and concentric LV remodeling in FRDA are associated at the tissue level with an expansion of the ECV and an increase in cardiomyocyte size. The adverse tissue remodeling assessed by ECV and τic is associated with more severe cardiomyopathy classification, suggesting a role for these markers in tracking disease progression. 

Quantitative assessment of Friedreich Ataxia via self-drinking activity

Ragil Krishna, Pubudu N Pathirana, Malcolm Horne, Louise Corben, David Szmulewicz; IEEE J Biomed Health Inform. 2021 Mar 25;PP. doi: 10.1109/JBHI.2021.3069007.

In this study, we propose an ataxia measuring device, in the form of a pressure canister capable of sensing certain kinetic and kinematic parameters of interest to quantify the impairment levels of participants particularly when engaged in an activity that is closely associated with daily living. In particular, the functional task of simulated drinking was utilised to capture characteristic features of disability manifestation in terms of diagnosis (separation of individuals with FA and controls) and severity assessment of individuals diagnosed with the debilitating condition of FA. Time and frequency domain analysis of these biomarkers enabled the classification of individuals with FA and control subjects to reach an accuracy of 98\% and a correlation level reaching 96\% with the clinical scores. 

NAD+ Precursor Supplementation in Friedreich's Ataxia

ClinicalTrials.gov Identifier: NCT04817111. A Phase 2a Study of NAD+ Precursor Supplementation in Friedreich's Ataxia 

Sponsor: Metro International Biotech, LLC; Collaborator: Children's Hospital of Philadelphia

Detailed Description: The primary focus for this protocol is safety and tolerability. We will systematically assess for adverse events using a safety monitoring uniform report form. We will also use cardiac 31-Phosphorus-Magnetic Resonance Spectroscopy (MRS) to measure the Phosphocreatine(PCr)/Adenosine triphosphate (ATP)- γ ratio before and after treatment with MIB-626. In addition, if time permits we will use proton (1H)-MRS to measure skeletal muscle nicotinamide adenine dinucleotide (NAD+) before and after treatment.

A severe form of autosomal recessive spinocerebellar ataxia associated with novel PMPCA variants

Yoko Takahashi, Masaya Kubota, Rika Kosaki, Kenjiro Kosaki, Akira Ishiguro; Brain and Development, Volume 43, Issue 3, 2021, Pages 464-469, doi:10.1016/j.braindev.2020.11.008. 

Spinocerebellar ataxia, autosomal recessive 2 (SCAR2) [MIM:213200] is a rare autosomal recessive disease of spinocerebellar ataxia associated with degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR2 is characterized by onset of impaired motor development and ataxic gait in early childhood. Recently, several PMPCA gene variants have been reported in SCAR2 patients with mild and non-progressive symptoms. PMPCA codes frataxin, which is crucial for iron biosynthesis in cells. 

**Evidences showed that MPP ( Mitochondrial-processing peptidase subunit alpha) is an enzyme that in humans is encoded by the PMPCA gene, it's involved in the proteolytic maturation of Frataxin, a protein responsible for iron homeostasis. Accordingly, MPP deficiency was shown to be involved in Friedreich ataxia, an autossomic recessive neurodegenerative disorder.

Progression characteristics of the European Friedreich's Ataxia Consortium for Translational Studies (EFACTS): a 4-year cohort study

Prof Kathrin Reetz, MD, Imis Dogan, PhD, Prof Ralf-Dieter Hilgers, PhD, Prof Paola Giunti, MD, Michael H Parkinson, MBBS, Caterina Mariotti, MD, Lorenzo Nanetti, MD, Prof Alexandra Durr, MD, Claire Ewenczyk, MD, Sylvia Boesch, MDWolfgang Nachbauer, MD, Thomas Klopstock, MD,, Claudia Stendel, MD, Francisco Javier Rodríguez de Rivera Garrido, MD, Christian Rummey, PhD, Prof Ludger Schöls, MD, Stefanie N Hayer, PhD Prof Thomas Klockgether, MD, Ilaria Giordano, MD, Claire Didszun, PhD, Myriam Rai, PhD, Prof Massimo Pandolfo, MD, Prof Jörg B Schulz on behalf of theEFACTS study group; The Lancet Neurology, Published:March 23, 2021 DOI:10.1016/S1474-4422(21)00027-2 

The European Friedreich's Ataxia Consortium for Translational Studies (EFACTS) investigates the natural history of Friedreich's ataxia. We aimed to assess progression characteristics and to identify patient groups with differential progression rates based on longitudinal 4-year data to inform upcoming clinical trials in Friedreich's ataxia.

The Role of Serum Levels of Neurofilament Light (NfL) Chain as a Biomarker in Friedreich Ataxia

Bernice Frempong, Robert B. Wilson, Kimberly Schadt and David R. Lynch; Front. Neurosci., 02 March 2021, doi:10.3389/fnins.2021.653241 

A deeper understanding of the mechanisms of NfL elevation in serum in FRDA is needed to make it a useful biomarker in FRDA.

The responsiveness of gait and balance outcomes to disease progression in Friedreich ataxia

Sarah C Milne, Seok Hun Kim, Anna Murphy, Jane Larkindale, Jennifer Farmer, Ritchie Malapira, Mary Danoudis, Jessica Shaw, Tyagi Ramakrishnan, Fatemeh Rasouli, Eppie M Yiu, Nellie Georgiou-Karistianis, Geneieve Tai, Zesiewicz Zesiewicz, Martin B Delatycki, Louise A Corben; doi: 10.1101/2021.03.18.434657 

The FARS USS and BBS are highly responsive and can detect change in a wide range of ambulant individuals with FRDA. However, therapeutic effects in children may be best measured by the DGI.

In vivo survival and differentiation of Friedreich ataxia iPSC-derived sensory neurons transplanted in the adult dorsal root ganglia

Viventi S, Frausin S, Howden SE, Lim SY, Finol-Urdaneta RK, McArthur JR, Abu-Bonsrah KD, Ng W, Ivanusic J, Thompson L, Dottori M.; Stem Cells Transl Med. 2021 Mar 18. doi: 10.1002/sctm.20-0334. Epub ahead of print. 

 Our data showed survival and differentiation of hESC and FRDA iPSC-derived progenitors in the DRG 2 and 8 weeks post-transplantation, respectively. Donor cells expressed neuronal markers, including sensory and glial markers, demonstrating differentiation to these lineages. These results are novel and a highly significant first step in showing the possibility of using stem cells as a cell replacement therapy to treat DRG neurodegeneration in FRDA as well as other peripheral neuropathies.