62 years old Chinese female, presented with 12 years history of involuntary movements (dystonia and dyskinesia) of neck and peri-oral region, with emergence of delusion 2 years after the onset of involuntary movements. Associated with anxiety symptoms. Delusion resistant antipsychotic medications. Neurocognitive assessment persistently showed severe impairment of executive function, memory and visuoconstructional ability. Language impairment not severe but family noticed change in quality. No family history. History also suggestive of change in dietary preference.