Previously, we studied the spectrum of pathogenic variants of the CFTR gene in more than 1,500 CF patients living in different regions of the European part of Russia and determined the spectrum of the most common pathogenic variants of the CFTR gene and the ethnic features of their distribution (Stepanova et al., 2012; Petrova et al., 2016, 2020a; Petrova N. V. et al., 2019). The gene discussed is CFTR; the disease is cystic fibrosis.