Childhood-Onset Myoclonus-Dystonia Due to KCTD17 Mutation: A Case Report and Review of Diagnostic Challenges

Background: Myoclonus–dystonia (M-D) is a rare hyperkinetic movement disorder most commonly associated with SGCE mutations, while KCTD17 represents a less frequent but distinct genetic cause.

Case Report: A 23-year-old man with childhood-onset Tourette-like symptoms developed progressive dystonia, upper-limb–predominant dystonia, upper-limb–predominant myoclonus, and laryngeal involvement. Genetic testing identified a pathogenic KCTD17 mutation in the patient and his affected mother.

Discussion: This case illustrates that Tourette-like manifestations may occur as an early presentation of KCTD17-related myoclonus–dystonia and underscores the importance of longitudinal reassessment and genetic evaluation.

Highlights

This case describes a genetically confirmed KCTD17-related myoclonus–dystonia presenting with early Tourette-like features. It highlights the diagnostic complexity arising from overlapping phenomenology, the importance of longitudinal reassessment, and the role of genetic testing in atypical, progressive, or treatment-refractory tic-like presentations.