For ethnic Russian CF patients, a significant diversity of the spectrum of CFTR variants was shown: up to 98% of mutant alleles were caused by 110 variants, the most common were F508del (55%), CFTRdele2,3 (7.5%), 2143delA (2.7%), 3849 + 10kbC-T (2.3%), 2184insA (2.2%), N1303K (1.7%), G542X (1.5%), W1282X (1.2%), L138ins (1.1%), E92K (1.0%), and W1282R (0.7%) (Petrova et al., 2020a). Here, CFTR is linked to cystic fibrosis.