GEOGRAPHIC-DISTRIBUTION OF FRENCH-CANADIAN LOW-DENSITY-LIPOPROTEIN RECEPTOR GENE-MUTATIONS IN THE PROVINCE OF QUEBEC

A total of 35 homozygous and 1320 heterozygous patients with familial hypercholesterolemia (FH) was screened for the presence of six low-den sity lipoprotein receptor (LDLR) gene mutations previously reported am ong French-Canadians. The geographic distribution of patients' birthpl aces and the relative prevalence of these six mutations in the LDLR ge ne in the province of Quebec were compared. For this purpose, the 16 a dministrative regions of the province of Quebec were grouped into seve n geographic regions. The relative frequency of the six mutations diff ered in the seven regions: the > 15 kb deletion (Delta > 15 kb) had th e highest relative frequency in the Pas St-Laurent/Gaspesie region, an d the point mutation in exon 3 had the highest relative frequency in t he Saguenay-Lac-St-Jean/Cote-Nord region. In the Montreal area, the De lta > 15 kb and the mutation in exon 3 had prevalence rates of 71.2% a nd 13.0%, respectively, whereas the relative frequencies of the Delta > 15 kb and the point mutation in exon 3 in the Quebec city region wer e 57.5 and 21.8%, respectively. Finally, in Saguenay-Lac-St-Jean/Cote- Nord, the relative frequency of the Delta > 15 kb only reached 31.5% a nd the point mutation in exon 3, 59.2%. Thus, on the north shore of th e St. Lawrence River, the prevalence of the Delta > 15 kb decreases fr om west to north-east, whereas the relative frequency of the mutation in exon 3 appears to increase. These observations provide a better cha racterization of FH among French-Canadians of Quebec, a Canadian provi nce with a high prevalence of this inherited disease.