Spectrum of mutations in CFTR in Finland: 18 years follow-up study and identification of two novel mutations

Abstract Background The incidence of cystic fibrosis (CF) is low in the isolated Finnish population and the Finnish CF mutation spectrum has differed from many European countries. Methods We have analyzed the mutation spectrum and the geographical distribution of CF mutations in Finland covering the last 18 years (1987–2004). Results A total of 14 mutations were identified; two of them new, 774insT and S589T (G>C at 1898). The overall coverage of mutations was 97% (99/102 chromosomes). The most frequent mutations were F508del and 394delTT, found in 36% (37/102) and 35% (36/102) of the CF chromosomes respectively. Of the rare mutations, a mutation of presumable Slavic origin, CFTRdele2.3 (21 kb), was enriched in a rural isolate with a frequency of 5,9% (6/102), and a mutation that possibly indicates Swedish influence, 3659delC, was scattered throughout the country with a similar frequency of 5,9% (6/102). G542X, R1162X, R117H, 3732delA, 1898+3A>C, S1196X, S945L, W57R, 774insT and S589T were each identified in a number of chromosomes from one to three. Conclusions Our observations of the Finnish CF mutation spectrum fit well with the characteristics of Finland as a population of multiple local founder effects.