A polymorphism in the 5' UTR of the DEFB1 gene is associated with the lung phenotype in F508del homozygous Italian cystic fibrosis patients

Background: The identification of cystic fibrosis (CF) patients who are at greater risk of lung damage could be clinically valuable. Thus, we attempted to replicate previous findings and verify the possible association between three single nucleotide polymorphisms (SNPs c.-52G)A, c.-44C>G and c.-20G>A> in the 5' untranslated region (59 UTR> of the b defensin 1 (DEFB1> gene and the CF pulmonary phenotype. Methods: Genomic DNA from 92 Italian CF patients enrolled in different regional CF centres was extracted from peripheral blood and genotyped for DEFB1 SNPs using TaqMan® allele specific probes. In order to avoid genetic confounding causes that can account for CF phenotype variability, all patients were homozygous for the F508del CFTR mutation, and were then classified on the basis of clinical and functional data as mild lung phenotype (Mp, ns50) or severe lung phenotype patients (Sp, ns42). Results: For the c.-20G>A SNP, the frequency of the A allele, as well as the AA genotype, were s...