Molecular analysis of CFTR gene mutations among Iraqi cystic fibrosis patients

Cystic fibrosis (CF) is an autosomal recessive multisystem disease that results from mutation(s) of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. More than 2100 mutations and polymorphisms have been reported in this gene so far. Incidence and genotyping of CF are under-identified in Iraq. This study aims to determine the types and frequencies of certain CFTR mutations among a sample of Iraqi CF patients. Two groups of patients were included: 31 clinically confirmed CF patients in addition to 47 clinically suspected patients of CF. All confirmed patients had typical, moderate-severe clinical presentation and course of the disease. Molecular analysis was performed on the majority of enrolled patients using the CF-stripAssay® kit supplied by ViennaLab diagnostics, GmbH, Austria.

The mutation-detection rate from the tested 34 mutations in this study was 19.5% and the 8 detected mutations were as follows: 3120+1G>A and W1282X were found in 3 (4.17%) patients each; F508del and R1162X were found in 2 (2.78%) patients each; 3272-26A>G, R347P, I507del, and 2183AA>G were found in 1 (1.38%) patient each. Polymorphic variants of IVS8, namely 5T, 7T, and 9T, were detected in ~ 70%. These results were nearly similar to what was reported in regional countries.

Cystic fibrosis seems to be not rare as previously thought. 3120+1G>A and W1282X are the two most commonly detected mutations. F508del needs to be included in all future tests, while the I507del mutation was uniquely reported in this study but not in regional studies.