CFTR gene analysis in 207 patients with cystic fibrosis in southwest France:: high frequency of N1303K and 1811+1.6kbA>G mutations.

The large molecular heterogeneity in cystic fibrosis (CF) represents the main difficulty for the genotype characterization. Moreover, numerous studies have reported considerable variations in frequencies of cystic fibrosis transmembrane conductance regulator (CFTR) mutations in different populations. Material and methods. - We analyzed the genotype of 207 CF children living in southwest France. Results. - Among 50 identified mutations, we report for some of them a widely modified incidence compared with those observed in other regions of France. These differences were more significant in the subset of the CF chromosomes originating in southwest France. Thus, the 1811+1.6kbA>G mutation, rarely observed in the other French regions (< 0.5%), proved to be, with a frequency of 8.8%, the most frequent mutation after the F508 deletion (57%). The frequencies of N1303K, 1811+1.6kbA>G and R334W mutations were also clearly increased: 7.9 and 2.6%, respectively. Conclusion. - We show that the southwest of France is characterized by a specific mutational spectrum. We consider that these regional data on the spectrum of CF mutations are crucial to develop more accurate and less expensive molecular screening strategies for cystic fibrosis in France. (C) 2001 Editions scientifiques et medicales Elsevier SAS.