Spinocerebellar Ataxia Type 27B Natural History Study (SCA27B-NHS)

The investigators will perform an international, multi-center, multi-modal, and registry-based standardized prospective Natural History Study (NHS) in Spinocerebellar Ataxia Type 27B (SCA27B), including the presymptomatic phase of the disease (i.e. presymptomatic subjects at risk for SCA27B). Participants will be assessed annually. Clinical data, including clinician-reported outcomes and patient-focused outcomes, will be entered into a clinical database customized to the requirements of this specific study (SCA27B Registry; www.ataxia-registries.org). Digital-motor outcomes comprise digital gait assessment by wearable sensors, and digital assessment of upper limb movements by Q-Motor. At all study visits, participants will be asked to donate biosamples; and participants can elect to participate in sampling of blood, urine, CSF, and/or a skin biopsy. Based on this multimodal protocol, the study aims to determine the most sensitive, comprehensive, and reliable outcome measures for future therapeutic trials in SCA27B.