[The reproduction of families affected by Steinert's dystrophy in Saguenay (Quebec), 1885-1971: demographic parameters].

In the light of the literature in the field one would expect that the myotonic dystrophy (or Steinert) gene carries a severe selective disadvantage. Indeed this phenotype is commonly said to entail...sterility infant mortality and a lower nuptiality. In the worst cases it is not unlikely that the gene could eliminate itself through non-reproduction. [A model is developed and] tested in the Saguenay (Quebec) population known for its exceptionally high prevelance (1/475) of the disease. Authors have been able to use a computerized demographic and genealogical data base in order to study several demographic variables (fertility nuptiality mortality etc)....Case-control analyses produced very [few] differences between affected and control families suggesting no significant selective disadvantage associated with the gene. (SUMMARY IN ENG AND ITA) (EXCERPT)