ATXN2 is a modifier of phenotype in ALS patients of Sardinian ancestry

Neurobiol Aging. 2015 Oct;36(10):2906.e1-5. doi: 10.1016/j.neurobiolaging.2015.06.013. Epub 2015 Jun 25.


Intermediate-length CAG expansions (encoding 27-33 glutamines, polyQ) of the Ataxin2 (ATXN2) gene represent a risk factor for amyotrophic lateral sclerosis (ALS). Recently, it has been proposed that ≥31 CAG expansions may influence ALS phenotype. We assessed whether ATXN2 intermediate-length polyQ expansions influence ALS phenotype in a series of 375 patients of Sardinian ancestry. Controls were 247 neurologically healthy subjects, resident in the study area, age- and gender-matched to cases. The frequency of ≥31 polyQ ATNX2 repeats was significantly more common in ALS cases (4 patients vs. no control, p = 0.0001). All patients with ≥31 polyQ repeats had a spinal onset versus 73.3% of patients with <31 polyQ repeats. Patients with an increased number of polyQ repeats have a shorter survival than those with <31 repeats (1.2 vs. 4.2 years, p = 0.035). In this large series of ALS patients of Sardinian ancestry, we have found that ≥31 polyQ repeats of the ATXN2 gene influenced patients' phenotype, being associated to a spinal onset and a significantly shorter survival.

Keywords: Amyotrophic lateral sclerosis; Ataxin 2 gene; Genetic modifier.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyotrophic Lateral Sclerosis / genetics*
  • Amyotrophic Lateral Sclerosis / mortality
  • Ataxin-2 / genetics*
  • Female
  • Genetic Association Studies*
  • Humans
  • Italy
  • Male
  • Middle Aged
  • Phenotype*
  • Risk Factors
  • Survival Rate
  • Trinucleotide Repeat Expansion / genetics


  • ATXN2 protein, human
  • Ataxin-2