| Abstract: | OBJECTIVE: To determine the frequency of six mutations (F508del, G542X, G551D, R553X,R1162X, and N1303K) in patients with cystic fibrosis (CF) diagnosed, at a referralcenter, on the basis of abnormal results in two determinations of sweat sodium andchloride concentrations. METHODS: This was a cross-sectional study involving 70 patients with CF. The mean age ofthe patients was 12.38 ± 9.00 years, 51.43% were female, and 94.29% were White.Mutation screening was performed with polymerase chain reaction (for F508del),followed by enzymatic digestion (for other mutations). Clinical analysis wasperformed on the basis of gender, age, ethnicity, pulmonary/gastrointestinalsymptoms, and Shwachman-Kulczycki (SK) score. RESULTS: All of the patients showed pulmonary symptoms, and 8 had no gastrointestinalsymptoms. On the basis of the SK scores, CF was determined to be mild, moderate,and severe in 22 (42.3%), 17 (32.7%), and 13 (25.0%) of the patients,respectively. There was no association between F508del mutation and diseaseseverity by SK score. Of the 140 alleles analyzed, F508del mutation was identifiedin 70 (50%). Other mutations (G542X, G551D, R553X, R1162X, and N1303K) wereidentified in 12 (7.93%) of the alleles studied. In F508del homozygous patientswith severe disease, the OR was 0.124 (95% CI: 0.005-0.826). CONCLUSIONS: In 50% of the alleles studied, the molecular diagnosis of CF was confirmed byidentifying a single mutation (F508del). If we consider the analysis of the sixmost common mutations in the Brazilian population (including F508del), themolecular diagnosis was confirmed in 58.57% of the alleles studied. |
