Spinocerebellar ataxias (SCA) are rare neurological diseases that affect balance, coordination, and speech. This study focuses on types 1, 2, 3, and 6 of SCA. We want to learn how these diseases progress over time and which genes might influence their behavior. We aim to involve 800 participants across the USA, with visits every 6 or 12 months. In this study, we will take a small blood sample to study your DNA, which helps us understand your disease's genetic factors. Some of your blood may be stored for future research to develop new tests and treatments. Your name won’t be attached to your sample, ensuring your privacy. You can opt out of the genetic study or tissue repository part, but still participate in the rest of the study. You’ll also complete some tests and examinations. To join, you must have symptomatic ataxia, a confirmed SCA diagnosis, and be at least 6 years old. You cannot participate if you have certain other ataxias or are unwilling to join.

• Participation may last for an unknown period.
• Visits occur every 6 or 12 months.
• Blood samples collected for genetic research.