The molecular analysis of mutations in exons 4, 11 and 21 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in cystic fibrosis patients in Kermanshah, Iran

Introduction: Cystic fibrosis (CF) is a common genetic disorder in white populations with an autosomal recessive pattern, caused by mutations in the CFTR gene. The frequency of more than 1950 various mutations reported in the CFTR gene significantly varies in different populations. ∆F508 is a common mutation in exon 10, which is first addressed in the molecular analysis of the disease. Other exons are required to be investigated owing to failing to identify mutations in the patients. The present study was conducted to investigate mutations in exons 4, 11 and 21 of the CFTR gene using the sequencing method in CF patients in Kermanshah province, Iran.

Methods: The present descriptive study was conducted on all patients with CF presenting to the medical genetics center in Kermanshah in 2010-2011. After taking blood samples and extracting DNA using saturated NaCl solution, sequences of exons were amplified using PCR and sequenced for identifying mutations.

Results: The frequency of mutations was found to be respectively 0, 0 and 5.5% in exon 11, 21 and 4. The D110H mutation was found to be homozygous in one subject and heterozygous in another. Moreover, the 4029A>G polymorphism (12.9%) was found to be homozygous in two subjects and heterozygous in three others.

Conclusion: The D110H mutation is recommended to be included in the screening programs of the study population. The results obtained support the effects of ethnic and geographical factors on the distribution of CF mutations.