The 3120 +1G→A splicing mutation in CFTR is common in Brazilian cystic fibrosis patients

Cystic fibrosis patients from Rio de Janeiro, Brazil, were screened for mutations in exons 11 and 16 of the cystic fibrosis transmembrane conductance regulator gene (CFTR) by a nonradioactive single-stranded conformational polymorphism (SSCP) analysis technique. This procedure was used to evaluate the undefined mutations in one or both alleles of 64 cystic fibrosis patients. Unusual SSCP profiles were investigated further by sequence analysis. Two patients were shown to carry the G542X mutation (exon 11) and five had the splicing mutation 3120+1G→A (intron 16), one of them being homozygous for the mutation. This is the first report of the 3120+1G→A mutation in Brazil, where it appears to be a frequent disease-associated molecular alteration in the CFTR gene.