Genetic Variants and Clinical Characteristics in the Diagnosis of Children Aged Under 18 Years With Cystic Fibrosis in a Brazilian State.

Abstract

Objective: To describe variants in the CFTR gene and demographic and clinical characteristics of individuals with Cystic Fibrosis (CF) from a Brazilian State pediatric reference center upon diagnosis.

Methods: Cross-sectional retrospective cohort study of individuals with CF under 18 years old treated in a referral center between 2007 and 2023. Data was derived from medical records. A descriptive analysis of the variables at diagnosis, including pathogenic genetic variants in the CFTR gene, clinical findings, and demographic data.

Results: The population of 110 patients was predominantly male (54.5%) and white (66.4%). Age at diagnosis ranged from 13 days to 17 years (median = 2 months), 78.2% were diagnosed at < 2 years, and 50.9% were diagnosed following neonatal screening. The most frequent clinical manifestations at diagnosis were steatorrhea (70.0%), persistent respiratory symptoms (58.2%), and malnutrition (36.4%). The most common CFTR variants were F508del (49.0%), G542X (7.3%), and 3120+1G>A (5.9%). Eighty-four (76.4%) were eligible to use at least 1 of the 4 CFTR modulator therapies available in Brazil, and 29 were eligible for 3 therapies because they are homozygous for F508del.

Conclusion: Identification of CFTR variants at diagnosis can provide many benefits to patients, such as early interventions and CFTR modulator therapy, and is feasible in Brazil. Because each country may have different distributions of CFTR variants, it is essential to evaluate these distributions as we advance methodologies for gene variant detection, particularly in the contexts of newborn screening and diagnostic testing.