title: A neurophysiological study of myoclonus in patients with DYT11 myoclonus-dystonia syndrome.
abstract: Mutations in the epsilon-sarcoglycan (SGCE) gene have been associated with DYT11 myoclonus-dystonia syndrome (MDS). The aim of this study was to characterize myoclonus in 9 patients with DYT11-MDS presenting with predominant myoclonus and mild dystonia by means of neurophysiological techniques. Variously severe multifocal myoclonus occurred in all of the patients, and included short (mean 89.1 +/- 13.3 milliseconds) electromyographic bursts without any electroencephalographic correlate, sometimes presenting a pseudo-rhythmic course. Massive jerks could be evoked by sudden stimuli in 5 patients, showing a "startle-like" muscle spreading and latencies consistent with a brainstem origin. Somatosensory evoked potentials and long-loop reflexes were normal, as was silent period and long-term intracortical inhibition evaluated by means of transcranial magnetic stimulation; however, short-term intracortical inhibition revealed subtle impairment, and event-related synchronization (ERS) in the beta band was delayed. Blink reflex recovery was strongly enhanced. Myoclonus in DYT11-MDS seems to be generated at subcortical level, and possibly involves basal ganglia and brainstem circuitries. Cortical impairment may depend from subcortical dysfunction, but it can also have a role in influencing the myoclonic presentation. The wide distribution of the defective SCGE in DYT11-MDS may justify the involvement of different brain areas.
authors.affiliation: Department of Neurology (Extrapyramidal Movement Centre), IRCCS Foundation, Carlo Besta Neurological Institute, Milan, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Marelli
authors.forename: Laura
authors.initials: L
authors.lastname: Canafoglia
authors.forename: Federica
authors.initials: F
authors.lastname: Zibordi
authors.forename: Claudia
authors.initials: C
authors.lastname: Ciano
authors.forename: Elisa
authors.initials: E
authors.lastname: Visani
authors.forename: Giovanna
authors.initials: G
authors.lastname: Zorzi
authors.forename: Barbara
authors.initials: B
authors.lastname: Garavaglia
authors.forename: Chiara
authors.initials: C
authors.lastname: Barzaghi
authors.forename: Alberto
authors.initials: A
authors.lastname: Albanese
authors.forename: Paola
authors.initials: P
authors.lastname: Soliveri
authors.forename: Massimo
authors.initials: M
authors.lastname: Leone
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Panzica
authors.forename: Vidmer
authors.initials: V
authors.lastname: Scaioli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Pincherle
authors.forename: Nardo
authors.initials: N
authors.lastname: Nardocci
authors.forename: Silvana
authors.initials: S
authors.lastname: Franceschetti