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.