Biallelic mutations in the elaC ribonuclease Z 2 (ELAC2) gene cause a rare mitochondrial disease, the main features of which are hypertrophic cardiomyopathy, delayed psychomotor development, and usually death during childhood. Only 20 families have been reported with this syndrome. Neither movement disorders nor psychotic features have been described as part of the spectrum of ELAC2 mutations. We describe a patient with a complex hyperkinetic syndrome and acanthocytosis, harboring biallelic ELAC2 mutations.