CFTR gene sequencing in a group of Chilean patients with cystic fibrosis

Abstract

Introduction: Cystic fibrosis (CF) is an autosomal recessive genetic disorder caused by mutations of the CFTR gene, in which over 1,900 different mutations have been identified. In Chile, the diagnosis panel with the 36 most common mutations detects approximately 50% of all alleles, while for Caucasians, it is nearly 90%.

The objective of this study is to expand the capacity of mutational screening in Chilean patients and look for recurrent mutations at the national level. 

Method: The detection of unknown pathogenic alleles was assessed by CFTR gene sequencing in a selected group of patients from the National Cystic Fibrosis Foundation (NCFF). 39 patients, who met the CF diagnostic criteria and had only one allele identified according to the mutational panel, were studied. Massive sequencing was performed throughout the investigation and the main CFTR databases were used for analysis. 

Results: The second pathogenic allele was identified in 16 of 39 patients of this study (41%), finding eleven different mutations that had not been reported in our population. We believe that the reason is that one of the variants had not been previously described. 

Conclusions: Mutations that had been described mainly in Hispanic and/or Mediterranean populations were identified. We found a variation that had not been previously reported, but not enough recurrent mutations that could explain the low rate of detection were found. Knowledge about mutations can provide appropriate genetic counseling and will be critical to evaluate the potential use of new targeted therapies for treating them.