Progress and challenges in sporadic late-onset cerebellar ataxias

Sporadic late-onset cerebellar ataxia (SLOCA) is a syndrome defined by subacute or chronic and progressive ataxia occurring after the age of 40 years in individuals without a family history of ataxia. The 2022 publication of revised consensus diagnostic criteria for multiple system atrophy and the emergence of promising biomarkers provides a thorough diagnostic framework that now enables the diagnosis of numerous acquired causes of SLOCA, including autoimmune disorders and neurodegenerative diseases. The ongoing development and increased availability of DNA sequencing technology have uncovered several molecular causes of SLOCA besides spastic paraplegia type 7 and very late-onset Friedreich ataxia. These additional causes include sporadic genetic disorders, such as spinocerebellar atrophy type 27B, caused by GAA expansion in the FGF14 gene, and cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS), caused by biallelic expansions in the RFC1 gene. This Review presents an updated clinical approach to the diagnosis and management of SLOCA that focuses on the most important developments in this field. Future challenges are also discussed, including the identification of additional missing genetic causes of SLOCA, especially via the use of long-read genome sequencing, improvements in SLOCA prognostication and the implementation of clinical trials of neuroprotective interventions.