Prevalence of the F508del variant in patients with cystic fibrosis in northeastern Brazil: clinical and laboratory factors

Abstract

Objective: To describe the genetic profile of patients with cystic fibrosis in northeastern Brazil and correlate it with clinical and laboratory characteristics. Methods: This was a cross-sectional study, with descriptive and analytical elements, of patients followed during 2021 at a referral center for cystic fibrosis in the Brazilian state of Ceará. We analyzed pathogenic variants of genes that play a role in cystic fibrosis and their correlations with clinical variables (gender, age, weight, height, BMI, and nutritional status), laboratory variables (microbiology and sweat test results), and medications in use. Results: Of a total of 86 patients evaluated, 85 underwent genetic testing. Homozygous F508del mutations were identified in 60%, and 95% had a single F508del allele. Class IV or V mutations were seen in 4.6%. The majority of the mutations were in functional class I, II, or III. We found that a homozygous F508del mutation was significantly associated with BMI (p < 0.019), nutritional status (p < 0.03), and a positive sweat test result (p < 0.049), as well as identifying a significant association between the microbiology result and patient age (p < 0.001). Conclusions: In our sample, the proportion of patients who were homozygous for the F508del mutation was well above the national and international averages, which makes those patients potentially eligible for treatment with at least one CF transmembrane conductance regulator modulator. Keywords: Cystic fibrosis; Genotype; Phenotype; Prevalence.