Association of 14-bp insertion/deletion polymorphism of HLA-G gene with idiopathic recurrent miscarriages in infertility center patients in Yazd, Iran

Abstract

HLA-G is supposed to play a pivotal role in tolerance of the semi-allogeneic graft in pregnancy by inhibiting the cytotoxic functions of T and NK cells. A 14-bp insertion and/or deletion polymorphism in exon-8 has a possible role in HLA-G expression. The present study analyzed the 14-bp insertion/deletion polymorphism in normal pregnancy and recurrent miscarriage patients in order to discover a possible correlation between the 14-bp polymorphism and recurrent miscarriage (RM). In this study, genomic DNA from 200 RM patients and 200 normal fertile control individuals using the routine salting out method were isolated. Exon-8 of HLA-G gene of the two groups were amplified using polymerase chain reaction and analyzed by electrophoresis on 10% non-denaturing polyacrylamide gel electrophoresis containing ethidium bromide and visualized under ultraviolet light. HLA-G allele frequencies and genotypes in RM women and the fertile control group were compared using a Chi-square test. The results showed that there was a difference in allelic frequencies of 14-bp insertion polymorphism between fertile controls and RM patients; the frequency of +14 bp/−14 bp heterozygotes was significantly higher in RM patients as compared with fertile controls. Furthermore, the frequency of +14-bp insertion allele was significantly higher in those with RM as compared with normal fertile controls. From the findings here, it was concluded that a 14-bp insertion/deletion polymorphism in exon 8 could play a possible role in recurrent miscarriages. These results might ultimately be of significance for clinicians and those involved in understanding infertility and RM.