Myoclonus‐dystonia: An update

Abstract

Our knowledge of the clinical, neurophysiological, and genetic aspects of myoclonus-dystonia (M-D) has improved markedly in the recent years. Basic research has provided new insights into the complex dysfunctions involved in the pathogenesis of M-D. On the basis of a comprehensive literature search, this review summarizes current knowledge on M-D, with a focus on recent findings. We also propose modified diagnostic criteria and recommendations for clinical management.

The genetics of the dystonias – a review based on the new classification of the dystonias

“…It often improves with alcohol and is therefore sometimes known as alcohol-responsive dystonia. In most patients the myoclonus is the most prominent and incapacitating symptom 45 . Nygaard et al 46 localized a gene for MD, DYT11 (SGCE), to chromosome 7 (7q21-q23).…”

A Novel Mutation in Exon 6 of the Epsilon-Sarcoglycan Gene in Myoclonus Dystonia Syndrome

“…Recently, MDS in a patient with 18p deletion syndrome was also described [9]. A few sporadic cases with de novo SGCE mutation have also been reported [5]. Different genetic mutations in exon 3, exon 4, and also in exon 6 were previously reported underlying the importance to register novel mutations and to add them to the preexisting list of known mutations in order to ensure an as fast and cost-effective diagnostic procedure as possible [4,8,10,11].…”

“…The full phenotypic spectrum of this syndrome, however, is quite diverse and still being defined [2,5]. Although early disease onset, onset with both myoclonus and dystonia, and axial dystonia were detected significantly more often in the mutation carriers [6], there has been no clear phenotypegenotype associations identified to date suggesting other genetic or environmental factors as modifiers.…”

“…Subsequently, numerous mutations in this gene have been described [5]. A second MDS locus was mapped to chromosome 18p11 [7].…”

Treatment of Dystonia

“…Muscle relaxants such as orphenadrine, cyclobenzaprine, metaxalone, carisoprodol, methocarbamol, and chlorzoxazone may help treat pain associated with muscle spasm. Benzodiazepines, such as clonazepam, diazepam, and lorazepam, may be used to treat various forms of dystonia, and is especially useful for myoclonus-dystonia [25]. Sodium oxybate was demonstrated to be efficacious in a pilot study for the treatment of alcohol-responsive disorders, such as myoclonus-dystonia [26].…”