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Título

Myoclonus-Dystonia of Probable Genetic Etiology: case report with motor symptoms responsive to the use of Levodopa

RESUMO

Case presentation: Female, 21 years-old, without relevant family history, present to our service of movement disorders due tremor. Around 7-years-old, she had tremors exacerbated in moments of mood changes and it was common to drop objects, especially in morning. After ten years the symptoms were more evident in the left upper limb and interfered with her daily life, and since then there has been progression to the contralateral upper and lower limbs. In addition, she initiated movements described as “muscle spasms”, which were often painful. In our evaluation, she had increased tone and trophism in the left sternocleidomastoid and trapezius and in the extensor and flexor muscles of upper limbs. Stereotyped involuntary movements more intense on the left in upper limbs, of low frequency and high amplitude, less evident on lower limbs, bilateral oromandibular dyskinesia. Ultra-rapid movements, especially in shoulders and arms. No other alterations on neurological examination. MRI and laboratorial tests were normal. Electroneuromyography showed postural and intention tremor, bilateral and asymmetric, predominance in the left upper limb and frequency of 6Hz. Subsequently, Levodopa+Benserazide 100/25mg tree doses daily was started, with substantial improvement in symptoms.
Discussion: Myoclonus-dystonia (M-D) is an autosomal-dominant movement disorder caused by mutations in Epsilon-Sarcoglycan (SGCE) gene, located on chromosome 7q21. The onset of symptoms usually occurs in the first decade of life. It manifests with myoclonus that most often affect the trunk, cervical region and upper limbs; and dystonia also in the upper limbs. There is a description of improvement in motor symptoms after alcohol libation. The diagnostic criteria proposed by Grünewald et al. (2008) classify M-D, according to the presence of family history and classic symptoms, as Definitive, Probable or Possible. Drugs that should be considered for treatment are benzodiazepines and anticholinergics, including in combination. Several other drugs need more robust studies.
Final Comments: M-D’s definitive diagnosis is limited by unavailability of genomic sequencing in most services. There is still a lack of therapies that change the prognosis of a disease that leads to significant functional impairment. And, in this sense, Levodopa may appear as a viable option, something little described in the literature.

Palavras Chave

Dystonia; Myoclonus; myoclonic dystonia; DYT-11; Movement Disorders