Characterization of a novel isolated deletion of the exon 3 within the CFTR gene: Relevance for phenotypic expression and genetic counseling

Abstract Objectives To characterize a novel deletion of exon 3 of CFTR gene and to evaluate the implications in Cystic Fibrosis (CF) care and genetic counseling. Design and methods We performed a wide mutational analysis of CFTR gene, using reverse dot blot, Multiplex Ligation-dependent Probe Amplification (MLPA) assay and Real Time Quantitative PCR, in a carrier male and two CF patients with the F508del mutation. Results We found a novel isolate 538 bp deletion of exon 3, described as 328del538 , giving rise to a nonsense codon 60 bp at the 3′ end of the new coding sequence or, alternatively, a novel splice site at the breakpoints. Conclusions The 328del538 is a rare lesion with the characteristics of a complete, but moderate, phenotypic expression. Its finding underlines the importance of improving the detection of mutations using different methods.