Genetic epidemiology of autosomal recessive spastic ataxia of Charlevoix-Saguenay in northeastern Quebec

Genet Epidemiol. 1993;10(1):17-25. doi: 10.1002/gepi.1370100103.


Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a disorder that has an elevated frequency in Saguenay-Lac-St-Jean (SLSJ) and Charlevoix, two geographically isolated regions in the past of northeastern Quebec. The incidence at birth and the carrier rate in SLSJ were estimated at 1/1,932 liveborn infants and 1/22 inhabitants, respectively, for the period 1941-1985. The mean inbreeding coefficient was twice higher and the mean kinship coefficient 3 times higher among the ARSACS families than among control families. In the SLSJ region, the birth places of the ARSACS individuals and their parents did not show a clustered distribution. The genealogical reconstruction suggests that the high incidence of ARSACS in SLSJ and Charlevoix is likely to be the result of a founder effect. Because the disease is apparently unknown elsewhere in the world and a high proportion of French Canadians presently living in eastern Quebec have ancestors coming from Perche, a small region in France, it also suggests that a unique mutation accounts for most, if not all, of the ARSACS cases known in these regions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Consanguinity
  • Genes, Recessive
  • Heterozygote
  • Humans
  • Incidence
  • Muscle Spasticity / epidemiology*
  • Muscle Spasticity / genetics*
  • Quebec / epidemiology
  • Spinocerebellar Degenerations / epidemiology*
  • Spinocerebellar Degenerations / genetics*