Analysis of 40 known cystic fibrosis mutations in South African patients

A total of 140 South African (SA) Caucasoid cystic fibrosis (CF) families were analysed for the common CF mutation, ΔF508. The 52 non-ΔF508 CF chromosomes in a subset of 127 of these families were also tested for 39 other known CF mutations. The most frequent mutation, apart from ΔF508 (which occurs at a frequency of 79%), was G542X (1.3%). Four other mutations, R553X, S549N, 621 + 1G→T and N1303K, were each found in single families. The other 35 mutations remained unidentified in this sample of CF families. Since 83% of SA Caucasoid CF mutations have been identified, diagnosis by mutation analysis will be possible in only 69% of CF cases. When a diagnosis has been confirmed by a positive sweat test, a combination of linked marker analysis and mutation detection will be necessary if prenatal diagnosis and carrier detection are to be offered in the remaining families.