Phenotypic expression of the p.Leu1077Pro CFTR mutation in Sicilian cystic fibrosis patients

BACKGROUND: The p.Leu1077Pro CFTR mutation was firstly described in 1992 as a mild allele that confers a pancreatic sufficiency phenotype but the information collected in database CFTR2 lead to consider p.Leu1077Pro as a severe CF mutation. Although it is typical of Southern Italy, p.Leu1077Pro is not included in the mutation panel firstly tested in individuals originated from this area. The aim of our study was to describe prevalence and clinical features in patients bearing this mutation followed in our Cystic Fibrosis Centre to demonstrate that this mutation should be included in the mutation panel firstly tested in patients originated from Southern Italy. FINDINGS: We reviewed data from a cohort of 111 cystic fibrosis patients. 4 patients who were heterozygous for the p.Leu1077Pro mutation were included in the study. In our Cystic Fibrosis Centre, the prevalence of p.Leu1077Pro is 3.6% among all mutations. All patients had positive sweat test values, pancreatic insufficiency and pulmonary exacerbations. One out of four patients even showed both FEV1 and FVC values significantly below the normal range, the presence of bronchiectasis and chronic Pseudomonas aeruginosa colonization. CONCLUSIONS: We found that the p.Leu1077Pro CFTR mutation is associated with a classic CF phenotype confirming what is reported in CFTR2 database. The relatively high prevalence of p.Leu1077Pro associated with the severe clinical course of the disease in patients bearing this mutation is of interest for genetic counselling purposes, as it should be part of mutation panel to be tested in individuals originated from Southern Italy.