Segmental brainstem myoclonus in ADCK3-Related ataxia: A novel phenomenon?

Segmental Brainstem Myoclonus (SBM) is a rare movement disorder characterized by rhythmic contractions of muscles innervated by brainstem segments. We report a 20-year-old patient with ADCK3-related spinocerebellar ataxia type 9 (SCAR9) presenting with sudden-onset myoclonic movements of the throat, tongue, and soft palate. Brain MRI showed stable findings, including dentate nucleus hyperintensities.