Hereditary myoclonus dystonia - rare entity diagnosed in younger children: report of a sporadic case with atypical features

Hereditary myoclonus dystonia is a rare movement disorder characterized with combination of myoclonic jerks with mild to moderate dystonia. Mostly caused due to changes in SGCE gene. Author report case of a 3 years old girl with atypical features of lower limb onset, mild dystonia, upper limb and neck myoclonic jerks and younger onset. She was detected to have pathogenic variant of SGCE gene. A diagnosis of myoclonus dystonia should be considered at an early age also like in our case so that treatment is initiated early for better results and improved quality of life and development.

Clinical characteristics and molecular genetic analysis of a myoclonus-dystonia syndrome family / 中华神经科杂志

Objective To summarize the clinical and the molecular genetic characteristics of type DYT11 dystonia by analyzing the clinical data and pathogenic gene mutation of type DYT11 dystonia of a myoclonus-dystonia syndrome (MDS) family.Methods A MDS family enrolled in the General Hospital of the People's Liberation Army Rocket Force in January 2018 was retrospectively analyzed.The clinical data of 11 affected family members were collected and genetic testing of four affected family members (including the proband) of the MDS family was conducted using a panel of dystonia-associated genes.Results The affected family members showed great differences in clinical characteristics and obvious clinical heterogeneity.Four affected family members had myoclonus and dystonia,two affected family members only had myoclonus and five affected family members only had dystonia.The results of genetic testing showed that the proband,his father and his grandfather had a mutation (c.835_839delACAAA) in SGCE gene,which is autosomal dominant and belongs to type DYT11 dystonia.Conclusions MDS shows clinical heterogeneity.Gene screening is of great importance for the diagnosis and treatment of dystonia with myoclonus.

A Familial Case of Myoclonus-Dystonia

BACKGROUND: Myoclonus-dystonia is a rare familial disease characterized by autosomal dominant inheritance, nonor slowly progressive axial myoclonus combined with dystonic posture, normal electroencephalography (EEG) finding, and dramatic response to alcohol intake. METHODS: Clinical manifestations were studied in a family with myoclonus-dystonia. Response to alcohol intake was investigated in affected adult patients. Brain magnetic resonance imaging (MRI) and other laboratory examination were performed in 3 patients. RESULTS: Eight (male: 5, female: 3) of the 14 biological family members through 4 generations were found to be affected by myoclonus-dystonia on neurological examinations. Another 5 members (male: 3, female: 2) were suspected to be affected in family history. All eight affected members showed axial myoclonus affecting the neck, trunk, and proximal muscles of the limbs. Six of them also had dystonia affecting the neck or the distal part of the arm. Myoclonus and dystonia were ameliorated dramatically after small dose of alcohol intake. Brain MRI, EEG study, and ophthalmologic examination showed no abnormalities. CONCLUSIONS: Our patients showed clinical features compatible with myoclonus-dystonia. This is the first Korean family with myoclonus-dystonia.