[Diagnosis of cystic fibrosis with DNA techniques]

The extensive body of genetic and physical mapping data accumulated since the identification of the cystic fibrosis (CF) gene locus on chromosome 7 has made possible the molecular cloning of the gene. A deletion of three DNA base pairs, removing a phenylalanine residue from position 508 of the protein product, accounts for 40-85 per cent of CF mutations in most Western countries, the estimated figure for Sweden being 60 per cent. In the article are discussed findings for three additional mutations (G551D, R553X and G542X), only one allele out of 200 analysed having been found to manifest the R553X mutation alone. Also discussed are DNA techniques for detecting the common mutation, recent progress toward in vivo correction of the defect, and indications and possibilities for future screening programs.