en Pulmonology Original Article Original Article <strong>Background</strong>: Cystic fibrosis (CF) is a monogenic autosomal recessive disorder caused by pathogenic variants in the CF transmembrane conductance regulator (CFTR) gene on chromosome 7. While the &Delta;F508 mutation is globally predominant, accounting for about 70% of CF cases, Iran exhibits a highly heterogeneous CFTR mutation spectrum.&nbsp;<br> <strong>Objectives</strong>: This study aimed to investigate the molecular profile of CF in people from Mazandaran Province, northern Iran.&nbsp;<br> <strong>Methods</strong>: We included 17 patients with CF (7 males and 10 females) from unrelated families in Mazandaran Province. The polymerase chain reaction (PCR)-Sanger sequencing was used to find common CFTR pathogenic variants in 14 patients, while whole exome sequencing (WES) and confirmatory Sanger testing were used to identify rare or novel variants in three patients.<br> <strong>Results</strong>: Nine distinct pathogenic variants were identified, with c.19911del emerging as the most frequent (25% of mutant alleles), surpassing the globally dominant &Delta;F508 variant.&nbsp;<br> <strong>Conclusions</strong>: The findings highlight the region-specific genetic landscape of CF and emphasize the need for tailored diagnostic strategies in Iran. Cystic fibrosis (CF), Cystic fibrosis transmembrane conductance regulator (CFTR) gene, Whole exome sequencing, Pathogenic variants, Iran 301 308 http://jpr.mazums.ac.ir/browse.php?a_code=A-10-1380-1&slc_lang=en&sid=1 Soheila Hokmabadi dr_hokmabadi@yahoo.com 100319475328460014025 100319475328460014025 No Department of Pediatrics, Bou Ali Sina Hospital, Mazandaran University of Medical Sciences, Sari, Iran. Hossein Jalali hossein.jalaliakerdi@gmail.com 100319475328460014026 100319475328460014026 No Thalassemia Research Center, Hemoglobinopathies Institute, Mazandaran University of Medical Sciences, Sari, Iran. Muhammad Amirzadegan mohamad.amirzadegan@gmail.com 100319475328460014027 100319475328460014027 No Sinaye Mehr Research Center, Mazandaran University of Medical Sciences Sari,Iran. Mohammad Reza Mahdavi Mahdavi899@gmail.com 100319475328460014028 100319475328460014028 Yes Thalassemia Research Center, Hemoglobinopathies Institute, Mazandaran University of Medical Sciences, Sari, Iran.