The first described pathogenic variant c.2617G>T of the CFTR gene

Abstract

Cystic fibrosis (CF) is a disease caused by pathogenic variants in the CFTR gene. The greatest difficulty at the moment is assessing the contribution to the development of the disease of rare and previously unidentified genetic variants (mutations), mutations of uncertain clinical significance, as well as determining the genotype-phenotype relationship. Additional diagnostic methods are needed due to the large number of patients with borderline sweat test values. Purpose of the study: to study the pathogenicity of a newly identified variant of the nucleotide sequence of the CFTR gene based on assessing the functional activity of epithelial ion channels (ENaC, CFTR, CaCCs). Materials and methods: medical history data, method intestinal current measurement (ICM). Results: the patient had a severe course of the disease. Positive sweat test results, low fecal pancreatic elastase. The ICM method showed the absence of chlorine channel function. Conclusion: For the first time, the clinical features of a patient with the c.2617G>T genetic variant in the genotype have been described. The results of the examination and the clinical course of the disease correspond to the severe course of the disease. Additional use of the ICM method confirmed the absence of CFTR channel function in a patient carrier of this variant of the CFTR gene.