ATXN3 and cerebellar ataxia: In order to accomplish that, we have designed a descriptive study to 1) systematically describe the profiles and possible patterns of ataxia severity referred to individual SARA items scores in a sample of patients with genetically confirmed SCA3 at the beginning of the follow up in our reference unit, and 2) to study the relationships between single SARA items scores and visual evaluation of 123I-Ioflupane (DaTSCAN) single-photon emission computed tomography (SPECT) imaging, nerve conductions, electromyography and other clinical parameters.