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last update : 30-01-2013
Symbol SCA1
Location 6p23
Name spinocerebellar ataxia 1
Other name(s)
  • Menzel type OPCA
  • olivopontocerebellar atrophy I
  • cerebelloparenchymal disorder I
  • Schut-Haymaker type OPCA
  • Corresponding gene ATXN1
    Other symbol(s) OPCA1, OPCA4
    Main clinical features
  • ADCA, type I was characterized by usually midlife onset, with anticipation, ataxia, dysarthria, dysmetria, intention tremor, pyramidal and extrapyramidal symptoms, gaze-evoked nystagmus with mildly reduced saccade velocity, ophthalmoplegia, loss of cerebellar Purkinje cells and brainstem neurons, evolution with a 10-15 years progression
  • progressive loss of motor skills, usually beginning with impaired gait and balance
  • fatal progressive neurodegenerative disease of late onset characterized by cerebellar ataxia accompanied by varying degrees of oculomotor deficits, pyramidal and extrapyramidal signs and peripheral neuropathy
  • Genetic determination autosomal dominant
    Function/system disorder neurology
    Type disease
    Gene product
    Name ataxin 1
    Gene mutationChromosome rearrangementEffectComments
    repeat expansion   abnormal protein/gain of function more than 40 triplet (CAG) repeat amplification encoding a polyglutamine stretch, with meiotic and mitotic instability of the repeat, predominantly in the sperm cell and peripheral blood leukocytes, forming detectable aggregates colocalizing with proteasome in PML (POD/ND10) nuclear bodies, implying a protein misfolding
    Remark(s) . ANP32A mediates neuritic pathology in SCA1 (PMID: 2284877)