A polyglutamine expansion in ATN1 is responsible for dentatorubral-pallidoluysian atrophy (DRPLA) a progressive disorder of ataxia, myoclonus, epilepsy, intellectual deterioration and dementia (Koide et al., 1994; Nagafuchi et al., 1994). This evidence concerns the gene ATN1 and Dentatorubral pallidoluysian atrophy.