CFTR and cystic fibrosis: The choice of the spectrum of mutations for routine analysis is conditioned by the results obtained in the course of our own studies [14], studies conducted in different laboratories of the Russian Federation on independent samples of CF patients [6,12,16,17], and data on the prevalence of CFTR gene mutations in a global sample of CF patients published by the World Health Organization [18] and presented in the CFTR mutation database CFTR1 [19].