Objective: To present a case report of a patient with myoclonus-dystonia in whom a mutation in the epsilon-sarcoglycan gene which has not been previously described, was detected.

Background: Myoclonus-dystonia is a clinical syndrome characterized by childhood-onset alcohol-responsive myoclonus (usually the initial symptom), predominantly in the upper body, dystonia and psychiatric disorders, especially obsessive-compulsive disorder and anxiety. The main responsible gene is epsilon-sarcoglycan gene (SGCE), with an autosomal dominant inheritance pattern and maternal imprinting. Several pathogenic variations of the SGCE gene related to myoclonus-dystonia have already been described.

Method: A 41-year-old woman presented with brief muscle jerks since age 12, which improved with alcohol. Furthermore, she suffered from anxiety and had occasionally complained of neck and back stiffness. Her paternal grandmother and two paternal great aunts presented early-onset myoclonus which stabilized with age, tremor and parkinsonism, and her sister complained of mild tremor. Her father and brother were asymptomatic.

Results: At examination, the patient presented trunk, cervical and upper-limb myoclonus, as well as cervical dystonia. Brain magnetic resonance imaging, electroencephalogram, blood tests for secondary dystonia (including copper and ceruloplasmin) and cerebrospinal fluid analysis were all normal. A molecular study of the SGCE gene showed a previously undescribed heterozygous mutation (c.694_825+148delinsCAGTGCA o p.Asp229Glufs*14), which produces a premature stop codon (truncated protein) or an alternative splicing, both of them very probably pathogenic. After several pharmacological measures, she is currently in treatment with piracetam.

Conclusion: Myoclonus-dystonia is a well-described entity but its genetic substrate is complex and expanding. The SGCE gene mutation here communicated has a high probability of pathogenicity and should be taken into consideration when future patients are genetically tested and counselled.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/myoclonus-dystonia-syndrome-due-to-a-novel-mutation-in-the-epsilon-sarcoglycan-sgce-gene/