spinocerebellar ataxia type 2 (SCA-2); olivopontocerebellar atrophy, Holguin type

Epidemiology

• 6-18% of spinocerebellar ataxias

Pathology

• pigmented maculopathy with or without
  • ophthalmoplegia
  • extrapyramidal signs

Genetics

• mutation of SCA2 gene
• presumably trinucleotide CAG repeat expansion (poly-Gln) in SCA2 gene

Clinical manifestations

• slow saccadic eye movements
• may present in early infancy
  • hypotonia, developmental delay, dysphagia, retinitis pigmentosa
• may present in late adulthood
  • ataxia, slow saccades, hyporeflexia
• cognitive impairment has been described
• chorea & dystonia have been described

Radiology

• magnetic resonance imaging
  • cerebellar atrophy most prominent among spinocerebellar ataxias
  • cerebral atrophy with ventricular enlargement may be seen
  • brainstem atrophy

More general terms

• olivopontocerebellar atrophy
• spinocerebellar ataxia (SCA)
• polyglutamine expansion disorder

Database

• OMIM: https://mirror.omim.org/entry/183090
• OMIM: https://mirror.omim.org/entry/601517
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6311