Myoclonus-dystonia (M-D) is a genetically heterogeneous movement disorder with autosomal dominant inheritance. Clinically, the disorder is characterized by myoclonic jerks and dystonic movements which characteristically respond to alcohol. Psychiatric abnormalities are often a part of the phenotype. A major gene locus maps to the epsilon-sarcoglycan gene (SGCE, DYT11) on chromosome 7q21-22, which encodes a transmembrane protein that is widely expressed in the brain but is of unknown function. A classification of M-D diagnostic categories was recently proposed: Definite M-D refers to early onset myoclonus and dystonia or isolated myoclonus occurring predominantly in the upper half of the body with a positive family history for myoclonus and/or dystonia.
KeywordsUnknown Function Head Movement Transmembrane Protein Diagnostic Category Positive Family History
The patient exhibits myoclonic jerks which predominantly involve his hands and fingers bilaterally, occurring both at rest and during action. Axial jerks are occasionally present. In addition, dynamic retrocollis is prominent with superimposed myoclonic jerks of the head. Mild blepharospasm is also present.
Myoclonus-Dystonia syndrome.mp4 (MP4 18,850KB)