Methods for screening in cystic fibrosis.

Cystic fibrosis (CF) is the most common lethal autosomal recessive disorder in Whites, with an incidence of approx 1 m 2500 live births and a carrier frequency of approx 1 in 25. Since the discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene m 1989 (1-3), molecular genetics laboratories throughout the world have endeavored to identify the mutations present in their population of CF-bearing chromosomes. Since the entire CFTR gene and its intron-exon boundaries have been sequenced, mutation analysis in CF has become relatively simple, although time consuming. Generally, a number of different methods are applied to mutation analysis, but all involve an imtial step of amplification of part of the gene by polymerase chain reaction (PCR) (4), or a derivative of it, such as amplification refractory mutation system (ARMS) (5).