Alexis Brice, A. Lagueny, Lucie Guyant-Maréchal, Laurent Vercueil, C.P. Jedynak, G. Ponsot, Emmanuel Roze, Christine Tranchant, M.A. Cournelle, Didier Hannequin, F. Durif, Philippe Damier, Stéphane Thobois, S. Tezenas du Montcel, Bernard Echenne, J. L. Houeto, Fabienne Clot, Alexandra Durr, M. Vidailhet, Diane Doummar, Agnès Camuzat, Département de Biostatistique, Santé Publique et Information Médicale [CHU Pitié-Salpêtrière] (BIOSPIM ), CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Neurologie et thérapeutique expérimentale, Institut National de la Santé et de la Recherche Médicale (INSERM)-IFR70-Université Pierre et Marie Curie - Paris 6 (UPMC), Service de neurologie [Saint-Antoine], Université Pierre et Marie Curie - Paris 6 (UPMC)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-CHU Saint-Antoine [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Sorbonne Université (SU), Neurobiologie des processus adaptatifs (NPA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Clinique neurologique, Hôpital Laennec, Service de Génétique Cytogénétique et Embryologie [CHU Pitié-Salpêtrière], Service de Neurologie, Hôpital du Haut-L'Evêque, Service de Clinique Neurologique, CHU Grenoble, CHU Trousseau [APHP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Génétique médicale et fonctionnelle du cancer et des maladies neuropsychiatriques, Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital de La Milétrie, Service de neuropédiatrie, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Saint-Vincent de Paul, Hôpital neurologique et neurochirurgical Pierre Wertheimer [CHU - HCL], Hospices Civils de Lyon (HCL)-Hospices Civils de Lyon (HCL), Service de Pédiatrie, Centre Hospitalier du Pays d'Aix, Service de Neurologie [CHU Clermont-Ferrand], CHU Estaing [Clermont-Ferrand], CHU Clermont-Ferrand-CHU Clermont-Ferrand-CHU Gabriel Montpied [Clermont-Ferrand], CHU Clermont-Ferrand, Service de Neuropédiatrie, Hôpital Gui de Chauliac [Montpellier], Département de Neurologie, CHU Strasbourg-Hopital Civil, This work was supported by INSERM, Réseau National Dystonies and GIS-Maladies Rares, and the patients' associations AMADYS and Ligue Française Contre la Dystonie., Université Pierre et Marie Curie - Paris 6 (UPMC)-IFR70-Institut National de la Santé et de la Recherche Médicale (INSERM), CHU Saint-Antoine [AP-HP], CHU Gabriel Montpied [Clermont-Ferrand], CHU Clermont-Ferrand-CHU Clermont-Ferrand-CHU Estaing [Clermont-Ferrand], Hôpital Gui de Chauliac [CHU Montpellier], and Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)
Background: Myoclonus dystonia syndrome (MDS) is an autosomal dominant movement disorder caused by mutations in the epsilon-sarcoglycan gene ( SGCE ) on chromosome 7q21. Methods: We have screened for SGCE mutations in index cases from 76 French patients with myoclonic syndromes, including myoclonus dystonia (M-D), essential myoclonus (E-M), primary myoclonic dystonia, generalised dystonia, dystonia with tremor, and benign hereditary chorea. All coding exons of the SGCE gene were analysed. The DYT1 mutation was also tested. Results: Sixteen index cases had SGCE mutations while one case with primary myoclonic dystonia carried the DYT1 mutation. Thirteen different mutations were found: three nonsense mutations, three missense mutations, three splice site mutations, three deletions, and one insertion. Eleven of the SGCE index cases had M-D and five E-M. No SGCE mutations were detected in patients with other phenotypes. The total number of mutation carriers in the families was 38, six of whom were asymptomatic. Penetrance was complete in paternal transmissions and null in maternal transmissions. MDS patients with SGCE mutation had a significantly earlier onset than the non-carriers. None of the patients had severe psychiatric disorders. Conclusion: This large cohort of index patients shows that SGCE mutations are primarily found in patients with M-D and to a lesser extent E-M, but are present in only 30% of these patients combined (M-D and E-M).