Abstract
Background and Objectives
The FUT3 gene regulates the expression of Lewis blood group antigens mainly L^ea and L^eb. The Lewis negative phenotype, is the result of an inactivated FUT3 enzyme that lacks glycosidase activity. Several single nucleotide polymorphisms (SNPs) may cause enzyme inactivation with different racial distribution. This study aimed to determine the frequency of these SNPs in Iranian blood donors.
 
Materials and Methods
In this cross sectional descriptive study, one hundred blood donors from Tehran Blood Transfusion Center were analyzed. Genomic DNA was extracted and the coding sequence of FUT3 gene was amplified with specific primers. PCR products were directly sequenced. Haplotypes were inferred by SNP Analyzer software.
 
Results
A total of 15 SNPs including 10 nonsense SNPs were recognized. The frequency of most common SNPs was detected as 39%(202T>C), 37%(314C>T), 20%(59T>G), 9%(508G>A), and 8%(47G>C). Haplotype analysis revealed 13 haplotypes. The frequency of major haplotypes was detected as 66.2%(Le), 17.5%(le^202,314), 4.3 %(le^47,202,314), 4.1 %(le⁵⁹), and 3.4%(le^59,508).
 
Conclusions 
Our findings indicate that 202T > C, 59T > G and 508G > A are useful as major SNPs for detection of Lewis-negative alleles in genotyping of Lewis blood groups; they can also play an effective role in large-scale studies associated with diseases in our population.