Neuroacanthocytosis is a progressive multisystem disease with a wide range of symptoms. The involuntary movements mainly include chorea and orofaciolingual dyskinesias. The descriptive name of the disease refers to the presence of abnormal erythrocytes in peripheral blood. Two siblings are presented. One young female had dystonia, self-mutilating behaviour, lip biting and eating difficulties. Her brother had repeated generalized epileptic seizures several years before developing choreatic movements and neuropsychiatric symptoms. Both had clinical signs of sensorimotor axonal polyneuropathy. Fresh blood smears in each patient contained between 15 and 20% acanthocytes compared to less than 2% in normal controls. Neuroacanthocytosis must be kept in mind in young adult patients without heredity for Huntington's disease and the diagnosis is easily confirmed when making a fresh blood smear.