Dystonia-Deafness Syndrome Caused by a beta-Actin Gene Mutation and Response to Deep Brain Stimulation

Introduction: Dystonia-deafness syndrome is a distinct clinical presentation within the dystonia-spectrum. Although several genetic and acquired causes have been reported, etiology remains unknown in the majority of patients.

Objectives: To describe two patients with dystonia-deafness syndrome due to a beta-actin gene mutation.

Methods: We report on disease course, genetic testing, and management of 2 patients, mother and daughter, presenting with dystonia-deafness syndrome.

Results: After exclusion of known dystonia-deafness syndrome causes, whole-exome sequencing revealed a beta-actin gene mutation (p.Arg183Trp) in both patients. Although beta-actin gene mutations are generally associated with developmental Baraitser-Winter syndrome, dystonia-deafness syndrome has been reported once in identical twin brothers. Bilateral GPi-DBS led to a significant decrease of dystonia and regain of independency in our patients.

Conclusion: The p.Arg183Trp mutation in the beta-actin gene is associated with the clinical presentation of dystonia-deafness syndrome, even with only minimal or no developmental abnormalities of Baraitser-Winter syndrome. GPi-DBS should be considered to ameliorate the invalidating dystonia in these patients. (C) 2016 International Parkinson and Movement Disorder Society.