The IFRD1 (57460C>T Polymorphism) Gene: A Negative Report in Cystic Fibrosis Clinical Severity

Abstract

Cystic fibrosis (CF) is an autosomal recessive disease caused by more than 1,900 mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. In CF, one intriguing aspect is that patients, with same CFTR mutation, can have high clinical variability. Thus, the CFTR genotype does not seem to be the only determining factor in the clinical severity modulation. Therefore, the modifier genes and the environment must be considered. The IFRD1 (Interferon-related developmental regulator 1) gene, acts on the immune system and in the recruitment of immune cells, and consequently could be a modulator. In our data we included 88 CF patients, diagnosed by CFTR mutation screening and positive sweat test. The 57460C>T polymorphism screening in the IFRD1 gene was made by polymerase chain reaction associated to enzymatic digestion. A genotypic comparison was performed with 23 CF clinical variables. The data was analyzed by the SPSS program considering α=0.05. The patients were analyzed considering the CFTR genotype characteristic by mutation class. In our data 64.77% of patients had mutations of classes I, II or III in the CFTR gene. The IFRD1 polymorphism frequency was 28 (12.99%), 35 (75.32%) and 25 (11.69%) to the CC, CT and TT genotypes, respectively. In our study, the 57460C>T polymorphism in the IFRD1 gene was not associated with the CF clinical variables. The analysis was performed with and without consideration of the CFTR genotype, and after correction for multiple testing (Bonferroni test), no positive association was observed in both cases. Taking into account our results, in the CF patients population analyzed, there were no associations of the 57460C>T polymorphism in the IFRD1 gene with the CF clinical variables.