Case study: childhood-onset tardive dyskinesia versus choreoacanthocytosis.

A male adolescent presented with aggression, depressed mood, and severe movement disorder that developed at age 5 after exposure to neuroleptics. Evaluation revealed acanthocytes in his blood, which led to a differential diagnosis of tardive dyskinesia versus choreoacanthocytosis. However, this is unusually young age of onset for these conditions. Differential diagnosis, medication management of the movement disorder, and pathophysiological mechanisms in tardive dyskinesia and choreoacanthocytosis are discussed.