New practical definitions for the diagnosis of autosomal recessive spastic ataxia of Charlevoix-Saguenay

Autor: Rodrigue Rossignol, Isabelle Coupry, Michel Koenig, Magalie Barth, Cyril Goizet, Nadège Bellance, Dominique Bonneau, Agnès Guichet, Diana Rodriguez, Christelle M. Durand, Nada Houcinat, Julie Bouron, Sébastien Moutton, Julie Lavie, Sandra Chantot-Bastaraud, Julie Pilliod, Alexandra Durr, Karine Nguyen, Alexis Brice, Didier Hannequin, Giovanni Benard, Mathieu Anheim, Perrine Charles, Christel Thauvin-Robinet, Alexandra Afenjar, Elise Maurat, Guillaume Fromager, Patrick Berquin, Didier Lacombe, Caroline Rooryck, Dan Milea, Sylvie Forlani, Philippe Convers, Elisabeth Maillart, Christophe Verny, Stéphanie Valence, Julien Van-Gils, Fanny Mochel, Christophe Hubert, Giovanni Stevanin, Lucie Guyant-Maréchal, Lydie Burglen, Gaetan Lesca
Rok vydání: 2015
Předmět:
Zdroj: Annals of Neurology. 78:871-886
ISSN: 0364-5134
Popis: Objective Autosomal recessive spastic ataxia of Charlevoix–Saguenay (ARSACS) is caused by mutations in the SACS gene. SACS encodes sacsin, a protein whose function remains unknown, despite the description of numerous protein domains and the recent focus on its potential role in the regulation of mitochondrial physiology. This study aimed to identify new mutations in a large population of ataxic patients and to functionally analyze their cellular effects in the mitochondrial compartment. Methods A total of 321 index patients with spastic ataxia selected from the SPATAX network were analyzed by direct sequencing of the SACS gene, and 156 patients from the ATAXIC project presenting with congenital ataxia were investigated either by targeted or whole exome sequencing. For functional analyses, primary cultures of fibroblasts were obtained from 11 patients carrying either mono- or biallelic variants, including 1 case harboring a large deletion encompassing the entire SACS gene. Results We identified biallelic SACS variants in 33 patients from SPATAX, and in 5 nonprogressive ataxia patients from ATAXIC. Moreover, a drastic and recurrent alteration of the mitochondrial network was observed in 10 of the 11 patients tested. Interpretation Our results permit extension of the clinical and mutational spectrum of ARSACS patients. Moreover, we suggest that the observed mitochondrial network anomalies could be used as a trait biomarker for the diagnosis of ARSACS when SACS molecular results are difficult to interpret (ie, missense variants and heterozygous truncating variant). Based on our findings, we propose new diagnostic definitions for ARSACS using clinical, genetic, and cellular criteria. Ann Neurol 2015;78:871–886
Databáze: OpenAIRE