Tardive dyskinesia is a collection of symptoms related to the side effects of neuroleptic medications that can mimic other types of disorders. Accurate diagnosis can be challenging, as there is no single test for tardive dyskinesia.

Female patient, 64 years old, with personal history of Chronic Myeloid Leukaemia and psychosis since forth decade, currently medicated with quetiapine 350 mg/day, risperidone IM 50 mg 15/15 days and trazodone 150 mg/day (previously medicated with haloperidol, amisulpride and olanzapine). She started with involuntary movements interpreted as tardive dyskinesia after 2 years on neuroleptic treatment. The difficult control of involuntary movements motivated the reference to ambulatory Neurology department. The review of personal history suggested a family history of involuntary movements and psychiatric illness. Physical examination showed generalized choreic movements. The analytical and imagiologic study was unremarkable. The presence of family history and involuntary movements atypical to be classified as tardive dyskinesia supported a genetic test for Huntington's disease who detected a CAG expansion with 43 repetitions in HTT gene. Despite treatment with amantadine and riluzole she maintains disease progression and evident cognitive deterioration.

The diagnostic process of involuntary movements may involve more than one physician and requires the review of a detailed medical history, a physical examination and a neuropsychological evaluation in order to determine whether one is indeed suffering from tardive dyskinesia or a different neurological disorder.

The authors have not supplied their declaration of competing interest.