A novel SGCE gene mutation causing myoclonus dystonia in a family with an unusual phenotype.

BACKGROUND Myoclonus dystonia is an autosomal dominant dystonia-plus syndrome, characterized by symptom variability within families. Most often is the myoclonus the most debilitating symptom, and many patients report myoclonus reduction after alcohol intake. In several families, mutations in the SGCE gene have been identified. METHOD We report of a three-generation family with myoclonus dystonia displaying a varied phenotype and maternal imprinting. Additionally, this family displays some unusual clinical presentations including alcohol-induced dystonia in an adult man, which will be discussed. RESULTS A novel mutation c.386T>C [p.I129T] was found within exon 3 of the SGCE gene in all three affected family members. In addition, two additional mutations [c.305G>A and IVS3+15G>A], judged to be polymorphisms in the SGCE gene, were found in two affected and one healthy family member. CONCLUSIONS This report presents a novel mutation in the SGCE gene causing myoclonus dystonia and extends the phenotype of myoclonus dystonia to also include alcohol-induced dystonia.