Spinocerebellar ataxia type 50 (SCA50)

Written and reviewed by Dr Ibrahim Imam, Consultant Neurologist. Last reviewed .

Spinocerebellar ataxia type 50 (SCA50). This is caused by GAA repeat mutations in the NPTX1 gene on chromosome 17. Fully referenced neurology checklist.

Genetics

  • This is caused by GAA repeat mutations in the NPTX1 gene on chromosome 17
  • The gene is also associated with infantile ataxia and secondary generalised epilepsy
  • The transmission is autosomal dominant
  • The mean onset age is 61 years: it may be as young as 6 years

Movement disorders

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Oculomotor features

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Cognitive features

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Other clinical features

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Magnetic resonance imaging (MRI) brain

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References

  1. Coutelier M, Jacoupy M, Janer A, et al. NPTX1 mutations trigger endoplasmic reticulum stress and cause autosomal dominant cerebellar ataxia. Brain 2022; 145:1519-1534.
  2. Schöggl J, Siegert S, Boltshauser E, Freilinger M, Schmidt WM. A de novo missense NPTX1 variant in an individual with infantile-onset cerebellar ataxia. Mov Disord 2022; 37:1774-1776. 
  3. Rafehi H, Read J, Szmulewicz D, et al. An intronic GAA repeat expansion in FGF14 causes autosomal dominant adult-onset ataxia SCA50/ATX-FGF14. Am J Hum Genet 2022; 110:105-119.
  4. Helmchen C, Koch PJ, Girard G, Brüggemann N, Machner B, Sprenger A. NPTX1-related oculomotor apraxia: an intra-hemispheric disconnection disorder. J Neurol 2022; 269:3931-3936.
  5. Deppe J, Deininger N, Lingor P, Haack TB, Haslinger B, Deschauer M. A novel NPTX1 de novo variant in a late-onset ataxia patient. Mov Disord 2022; 37:1319-1321.

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