Null Allele Frequencies at HLA-G Locus in Iranian Healthy Subjects

Background: HLA-G gene contains 15 alleles including a null allele, HLA-G*0105N. Previous studies have shown that HLA-G*0105N does not encode the complete HLA-G1 or HLA-G5 isoforms but encodes a functional HLA-G protein with the ability to in-hibit NK cell cytolysis. Thus, although the biological functions of HLA-G1 and HLA-G5 proteins are abrogated, other isoforms such as HLA-G2 can replace their roles. Stud-ies on the null allele of HLA-G gene could be useful in understanding the genetic vari-ants of HLA-G alleles in ethnic groups. Objective: The goal of this research was to de-termine the frequency of HLA-G*0105N null allele in Iranian healthy subjects. Meth-ods: The frequency of HLA-G*0105N null allele was evaluated in Iranian healthy sub-jects by PCR-RFLP method. Genomic DNA was isolated from the whole blood of 100 randomly selected, healthy, unrelated Iranian individuals using salting-out technique followed by PCR amplification of the exon 3 of HLA-G gene. PCR products were di-gested with PpUM-1 and the resulted fragments were analyzed using gel electrophore-sis. Results: In this study the restriction enzyme digestion confirmed homozygous HLA-G*0105N null allele for 9 % of the population. Furthermore obtained results indi-cated that the total frequency of HLA-G*0105N null allele was 20 % in the studied population of Iran. Conclusion: The final data analysis showed that the total frequency of this allele in Iranian people was higher than other ethnic groups that have been stud-ied so far.