The differential diagnosis of dizziness is broad and can include both vestibular and autonomic pathology. Vestibular dizziness is typically described as a sensation of movement (e.g. the world is spinning) while dizziness related to autonomic dysfunction is typically described as symptoms of orthostatic intolerance (e.g. postural lightheadedness)....
✦ The floor
Discussion
Signed responses from readers of the wire.
Audiologists and vestibular specialists seeing isolated downbeat nystagmus without ataxia (loss of coordination) should consider rare genetic conditions like SCAR10 in the differential—but this single case report does not justify protocol changes.
Recognizing atypical vestibular presentations of rare genetic disorders can reduce diagnostic delays and prompt appropriate genetic referral in dizziness clinics.
- 01Downbeat nystagmus (involuntary downward eye movements) appeared before classic balance symptoms in SCAR10.
- 02SCAR10 is a rare autosomal recessive spinocerebellar ataxia with limited published vestibular phenotype data.
- 03Case highlights the importance of genetic workup when central nystagmus lacks an obvious cause.
- 04Supports broadening the differential diagnosis of unexplained downbeat nystagmus in young patients.
- 05Published as a case report in Neurogenetics 2026; evidence limited to a single patient.
Downbeat nystagmus without ataxia can be an early vestibular manifestation of SCAR10.
studypartially supported- PMID
- 42702636
- DOI
- 10.1007/s10048-026-00939-7.
- Journal
- Neurogenetics
- Publication type
- case_report
- Evidence level
- 4
- Sample size
- 1
- Population
- Single patient presenting with downbeat nystagmus as an early manifestation of SCAR10
- Intervention
- Clinical and genetic characterization of early SCAR10 vestibular manifestations
Primary outcomes
Characterization of downbeat nystagmus as an early sign of SCAR10; Differential diagnosis of dizziness in SCAR10