CFTR and cystic fibrosis: In CF patients from the international CFTR2 database, the five most common mutations are F508del, G542X, G551D, N1303K, and W1282X in descending order of prevalence [17], a list which is different from the five most common Russian CFTR mutations, F508del, CFTRdele2.3, E92K, 1677delTA, and 3849+10kbC>T [14], including the results of our study.