Affiliations: Department of Biology, Science and Research Branch,
Islamic Azad University, Tehran, Iran | Cellular and Molecular Biology Research Center, Babol
University of Medical Sciences, Babol, Iran | Non-Communicable Pediatric Diseases Research Center,
Babol University of Medical Sciences, Babol, Iran | Genetic Department of Tehran University Of Medical
Scienses, Tehran, Iran | Endocrine Research Center of Tehran University of
Medical Sciences, Tehran, Iran
Note: [] Corresponding author: Haleh Akhavan Niaki, Cellular and
Molecular Biology Research Center, Babol University of Medical Sciences, Babol,
Iran. E-mail: halehakhavan@yahoo.com
Abstract: Background: Cystic fibrosis is a monogenic recessive disorder found
predominantly in Caucasian population. This disease arises from mutations in
the cystic fibrosis transmembrane conductance regulator (CFTR) gene. In this
study we consider poly T polymorphism c.1210-12T[5], c.1210-12T[7],
c.1210-12T[9] (T_{5}, T_{7}, T_{9}) in the intron 8 of CFTR gene in
normal individuals and cystic fibrosis patients in the north of Iran. Material and methods: 40 CF patients and 40 normal individuals were screened
for poly T polymorphism in intron 8 of CFTR gene using Reverse Dot Blot method
which was also used to detect p.Phe508del among CF patients. Results: T_{7} allele is the most prevalent in both normal and CF patients. Its
abundance is approximately 75%. T_{9} and T_{5} represent approximately
20% and 5% of alleles respectively. T_{7}/ T_{7} genotype is the most
present in both normal and CF patients with 72.5% and 60% prevalence
respectively. p.Phe508del was present in 13 CFTR alleles belonging to 7
patients with either homozygote T_{9}/ T_{9}, T_{7}/ T_{7}
or compound heterozygote T_{7}/ T_{9} genotypes. Conclusion: Contrary to the
Caucasians, T_{7} allele is more frequent in Northern Iranian CF patients.
The presence of p.Phe508del and T_{7} allele in the same framework is
reported for the first time in this part of the world. Further investigations
of other populations will help to understand whether p.Phe508del arose by
selection pressure in this part of the world or was imported from European
countries. The abundance of T_{5}, T_{7}, T_{9} alleles indicates that
this polymorphism can be used as one of the informative markers for detection
of normal and mutant alleles in prenatal diagnosis or carrier assessment in
families with previous history of the disease in regions with high degree of
CFTR mutation heterogeneity.
