Chorea-acanthocytosis (ChAc, also called choreoacanthocytosis) is a rare hereditary disease caused by a mutation in a gene that directs structural proteins in red blood cells. It belongs to a group of four diseases characterized under the name neuroacanthocytosis. When a patient's blood is viewed under a microscope, some of the red blood cells appear thorny. These thorny cells are called acanthocytes.

Other effects of the disease may include epilepsy, behaviour changes, muscle degeneration, and neuronal degradation similar to Huntington's disease. The average age of onset of symptoms is 35 years. The disease is incurable and inevitably leads to premature death.

Chorea-acanthocytosis is a very complex autosomal recessive adult-onset neurodegenerative disorder. It often shows itself as a mixed movement disorder, in which chorea, tics, dystonia and even parkinsonism may appear as a symptom.

This disease is also characterized by the presence of a few different movement disorders including chorea, dystonia etc.

Chorea-acanthocytosis is considered an autosomal recessive disorder, although a few cases with autosomal dominant inheritance have been noted.