Relations between C9orf72 expansion size in blood, age at onset, age at collection and transmission across generations in patients and presymptomatic carriers

Clémence Fournier, Mathieu Barbier, Agnès Camuzat, Vincent Anquetil, Serena Lattante, Fabienne Clot, Cécile Cazeneuve, Daisy Rinaldi, Philippe Couratier, Vincent Deramecourt, Mario Sabatelli, Serge Belliard, Martine Vercelletto, Sylvie Forlani, Ludmila Jornea, Alexis Brice, Sophie Auriacombe, Frédéric Blanc, Claire Bouteleau-Bretonnière, Mathieu CeccaldiMira Didic, Bruno Dubois, Charles Duyckaerts, Frédérique Etcharry-Bouix, Véronique Golfier, Didier Hannequin, Lucette Lacomblez, Isabelle Le Ber, Richard Levy, Bernard François Michel, Florence Pasquier, Catherine Thomas-Anterion, Jérémie Pariente, François Sellal, Eve Benchetrit, Hugo Bertin, Anne Bertrand, Anne Bissery, Stéphanie Bombois, Marie Paule Boncoeur, Pascaline Cassagnaud, Mathieu Chastan, Yaohua Chen, Marie Chupin, Olivier Colliot, Xavier Delbeucq, Christine Delmaire, Emmanuel Gerardin, Claude Hossein-Foucher, Pierre François Pradat, French Clinical and Genetic Research Network on FTLD/FTLD-ALS, PREVDEMALS and FTLD-Exome Study Groups

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


A (GGGGCC)n repeat expansion in C9orf72 gene is the major cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The relations between the repeats size and the age at disease onset (AO) or the clinical phenotype (FTD vs. ALS) were investigated in 125 FTD, ALS, and presymptomatic carriers. Positive correlations were found between repeats number and the AO (p < 10e−4) but our results suggested that the association was mainly driven by age at collection (p < 10e−4). A weaker association was observed with clinical presentation (p = 0.02), which became nonsignificant after adjustment for the age at collection in each group. Importantly, repeats number variably expanded or contracted over time in carriers with multiple blood samples, as well as through generations in parent-offspring pairs, conversely to what occurs in several expansion diseases with anticipation at the molecular level. Finally, this study establishes that measure of repeats number in lymphocytes is not a reliable biomarker predictive of the AO or disease outcome in C9orf72 long expansion carriers.

Original languageEnglish
Pages (from-to)234.e1-234.e8
JournalNeurobiology of Aging
Publication statusPublished (in print/issue) - 1 Feb 2019


  • Amyotrophic Lateral sclerosis
  • Anticipation
  • C9orf72
  • Frontotemporal dementia
  • Frontotemporal lobar degeneration
  • TDP-43


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