[Genealogical study of oculopharyngeal dystrophy at Saguenay-Lac-St-Jean, Quebec, Canada].

The genealogies of 28 proband affected with oculopharyngeal dystrophy (OPD) distributed in 28 families from Saguenay-Lac-St-Jean, a geographically isolated region of northeastern Quebec, were reconstructed. The analysis of these genealogies showed that the Montmagny and L'Islet counties are the most likely center of diffusion of OPD among the French Canadians, as suggested by Barbeau in 1966. A unique founder couple, J.E.-M.B., common to all 28 genealogies was found. The children of this couple emigrated in the 17th century from Poitou (France), a region where several families with OPD were recently ascertained.