RENAL DISEASE IN ADULT PATIENTS WITH CYSTIC FIBROSIS

Introduction and Aims: Cystic fibrosis is the most common autosomal recessive disease affecting the caucasian population, with a birth incidence ranging between 1:2500 and 1:1800. It is caused by mutations in the CFTR [cystic fibrosis transmembrane regulator] gene which is localized on 7 chromosome. Renal disease is reported as a relatively rare complication in adult patient with CF. We evaluated proteinuria and chronic renal failure in a population of patients with CF. Methods: A retrospective study was carried out in a referral center for CF at University of Messina in Italy. We identified all patients with renal disease, characterized by proteinuria and/or chronic renal failure (CRF), during the period 2007-2012 and reviewed their medical records. To assess the correlation between genotype and proteinuria, genetic mutations were evaluated. Results: From a population of 77 adult patients with CF, we identified 9 patients with proteinuria (11.7%), and 11 patients (14,28%) with chronic renal failure. Mean age was 35.6 (+5.1 SD) years, 55% were female and 33% had diabetes mellitus. Renal biopsy was performed in three patients because of nephrotic syndrome in one patient and proteinuria with renal failure in the other two patients. Renal amyloidosis was disclosed in two whilst IgAN in one patient. The ΔF508 mutation in homozygosis was present in 44% of patients with proteinuria(versus 27% of our CF population, Relative Risk 2.07), while genotype ΔF508/N1303K in 22%. ΔF508 allele mutation was present in 77.7% of proteinuric patients. Conclusions: Our study shows an higher prevalence of renal disease in patients with CF, than was previously described. The main reason may be related to increased life expectancy due to better management. Moreover patients with ΔF508 homozygosis had higher risk of proteinuria.