Hereditary disorders in the French Canadian population of Quebec. I. In search of founders.

Twenty-eight hereditary disorders are known to cluster in at least one region of Quebec, 24 of them in regions east of Quebec City, including 20 in the northeastern part of the province. Genealogies were reconstructed to identify the probable origin of 21 of these 28 disorders present in the French Canadian population. The results showed that most of the disorders were brought to Nouvelle-France by settlers coming from France in the seventeenth century. Only 249 of the 8483 settlers in Nouvelle-France contributed, as common founders, to these genealogies. The contribution of the province of Perche was significantly higher than expected from its relative weight to the founding nucleus of the French Canadian population in 19 disorders. Furthermore, 34 of the 48 different common founders from Perche were found in more than one disorder.