Tehran University Medical Journal

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background: Cystic fibrosis is a monogenic recessive disorder founds predominantly in caucasian population causes exocrine glands function defect. This disease arises from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Because of heterogeneity of the mutations in CFTR gene, phenotypic symptoms in this disease are very variable. In this study we consider poly T polymorphism (T₅, T₇, T₉) in the intron 8 of CFTR gene in normal individuals and cystic fibrosis patients in mazandaran province.
Methods: Forty cases of cystic fibrosis patients and 40 normal individuals were screened for poly T polymorphism in intron 8 of CFTR gene using Reverse Dot Blot method.
Results: T₇ allele is the most prevalent in normal individuals and CF patients and it's abundance is approximately 75%. T₉ and T₅ represent approximately 20% and 5% of normal or mutant alleles respectively. T₇/T₇ genotypes in normal individuals and CF patients are the most prevalent with 72.5% and 60% prevalence rate, respectively. T₅/T₉ and T₅/T₅ genotypes were not found. 22.5% of normal individuals and 30% of CF patients had heterozygote genotypes.
Conclusion: The abundance of T₅, T₇, T₉ alleles and the presence of 22.5-30% heterozygote genotypes in normal individuals and CF patients indicates that poly T polymorphism in intron 8 of CFTR gene can be used as a marker for detection of normal and mutant alleles in prenatal diagnosis or can be used in carrier assessment in families with previous history of the disease.

Background: Cystic fibrosis (CF) is a multiorgan autosomal recessive disorder. As CF is highly heterogeneous in Iran and many mutations have a low frequency, routine molecular diagnostic methods are not very efficient. The use of highly polymorphic intragenic markers not only can facilitate phenotype prediction in prenatal diagnosis by gene tracking, but also can lead to the demonstration of possible associations between haplotypes and specific mutations. We determined IVS8 polyT and M470V polymorphisms in exon 10 of CFTR gene in this case-control study.

Methods: Polymorphisms of IVS8 polyT in 53 patients with CF were referred to Amirkola children's Hospital of Babol University of Medical Sciences, 2007 to 2011 and 49 fertile healthy individuals were determined by reverse dot blot method. M470V polymorphism was analyzed by PCR-RFLP.

Results: In IVS8 polyT study, T7 was the most frequent allele in healthy individuals than patients with CF (respectively, 82.8% Vs. 77.2%). T9 was more abundant in patients with CF than normal individuals (respectively, 21.7% Vs. 7.4%, P=0.005). T9/T9 genotype was more frequent in patients than healthy individuals (respectively, 15.1% and 2%, P=0.032). Study for M470V polymorphism showed that M/V was the most common genotype in normal individuals and patients with CF (respectively, 49% and 40.4%). M-T9 haplotype was highly associated with the disease in both patients with CF and normal individuals (respectively, 19.1% and 2.4%, (P<0.001)

Conclusion: The allelic distribution and heterozygosity results suggest that both M470V and IVS8 polyT can be helpful in the prenatal diagnosis of CF in Northern Iranians with a positive family history of the disease.