VPS13A and chorea-acanthocytosis: Chorea-acanthocytosis (ChAc) is a rare hereditary disease caused by loss-of-function-mutations of the chorein encoding gene VPS13A (vacuolar protein sorting-associated protein 13A)7,13, leading to progressive autosomal recessive neurodegenerative disease characterized by severe pleotropic movement disorders, epilepsy, decline of cognitive functions, and variable erythrocyte acanthocytosis4,7,11,14–22.