Spinocerebellar ataxia type 2 (SCA2)

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

Spinocerebellar ataxia type 2 (SCA2). This is caused by mutations in the ataxin 2 (ATXN2) gene on chromosome 12. Fully referenced neurology checklist.

Genetics

  • This is caused by mutations in the ataxin 2 (ATXN2) gene on chromosome 12
  • It is a polyQ CAG repeat disorder
  • The normal repeat number is between 15-24
  • >35 repeats are pathogenic but a case with 31 repeats has been reported
  • The transmission is autosomal dominant
  • Onset is in the third to fourth decades

Ataxic features

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Other movement disorders

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Peripheral nerve features

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Magnetic resonance imaging (MRI) brain

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References

  1. Whaley NR, Fujioka S, Wszolek ZK. Autosomal dominant cerebellar ataxia type I: a review of the phenotypic and genotypic characteristics. Orphanet J Rare Dis 2011; 6:33.
  2. Spadaro M, Giunti P, Lulli P, et al. HLA-linked spinocerebellar ataxia: a clinical and genetic study of large Italian kindreds. Acta Neurol Scand 1992; 85:257-265.
  3. Ueyama H, Kumamoto T, Nagao S, Mita S, Uchino M, Tsuda T. Clinical and genetic studies of spinocerebellar ataxia type 2 in Japanese kindreds. Acta Neurol Scand 1998; 98:427-432.
  4. Kim JS, Kim JS, Youn J, et al. Ocular motor characteristics of different subtypes of spinocerebellar ataxia: distinguishing features. Mov Disord 2013; 28:1271-1277.
  5. Tojima M, Murakami G, Hikawa R, et al. Homozygous 31 trinucleotide repeats in the SCA2 allele are pathogenic for cerebellar ataxia. Neurol Genet 2018; 4:e283. 
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