Neuropathy in GAA ‐FGF14 Late‐Onset Cerebellar Ataxia (SCA27B ): Prevalence and Characteristics
Julian Theuriet, Lukas Paulet, Blandine Acket, Fabienne Ory‐Magne, Hocine Belbachir, Jean‐Baptiste Chanson, Françoise Bouhour, Chloé Laurencin, Caroline Froment Tilikete, Pierre Lardeux, Guillemette Clement, Armand Hocquel, Mathilde Renaud, Céline Bonnet, Cecilia Marelli, Sacha Weber, Camille Comet, Jean‐Philippe Azulay, Frédérique Fluchère, Giulia Coarelli, Anna Heinzmann, Claire Ewenczyk, Christophe Verny, Virginie Guillet‐Pichon, Lucie Guyant‐Marechal, Clément Desjardins, Audrey Riou, Bertrand Degos, Sandra Mercier, Cyril Goizet, Manon Degoutin, Chloé Angelini, Brice Laurens, Adrian Degardin, Nicolas Carrière, Gwenaël Le Guyader, Vincent Schneider, Gwendoline Dupont, Quentin Thomas, Maxime Merindol, Elsa Besse‐Pinot, Aurélie Méneret, Emmanuel Roze, Alexandra Durr, Stéphane Thobois, Mathieu Anheim, Thomas Wirth, Antoine Pegat ABSTRACT
Background
This study aimed to investigate the prevalence, characteristics, and determinants of peripheral neuropathy in a large cohort of patients affected by spinocerebellar ataxia type 27B (SCA27B), a late‐onset cerebellar ataxia caused by heterozygous GAA repeat expansions in the first intron of the FGF14 gene.
Methods
A retrospective, multicenter study in which medical records of SCA27B patients diagnosed between January 2023 and July 2024 in 21 French ataxia/neurogenetic centers were reviewed. Those who had undergone electrodiagnostic study were included.
Results
Among 332 SCA27B patients, 170 had undergone an electrodiagnostic study and were included. Forty‐two (25%) were diagnosed with neuropathy: 16 with length‐dependent axonal sensorimotor neuropathy, 24 with length‐dependent axonal sensory neuropathy, one with sensory, and one with motor neuronopathy. Neuropathy was associated with male sex, older age at electrodiagnostic study, and risk factors for neuropathy but not with GAA expansion sizes. Patients with neuropathy had more severe disability at the last visit (median SARA score 12 vs. 8, p = 0.0024).
Conclusions
The prevalence of neuropathy in SCA27B patients was similar to that reported in the elderly general population. Neuropathies were predominantly non‐specific length‐dependent axonal neuropathies, primarily driven by aging and known risk factors rather than the underlying genetic abnormality.