Bi-pallidal deep brain stimulation as an effective therapy in atypical two-stage evolution adult-onset KMT2B-related dystonia

We report an adult-onset KMT2B-related dystonia with a two-stage evolution: focal cervical onset followed by rapid generalization. Whole genome sequencing identified a likely pathogenic KMT2B variant. Bi-pallidal deep brain stimulation led to an 83% motor improvement, highlighting its therapeutic potential in late-onset atypical two-stage evolution KMT2B-dystonia.