Analysis of human leukocyte antigen-G polymorphism including intron 4 in Japanese couples with habitual abortion

PROBLEM: The purpose of this study was to clarify whether there is a differ ence between the allele frequency of human leukocyte antigen (HLA)-G in hea lthy Japanese people and that of Japanese couples with habitual abortion. METHOD OF STUDY: Exons 2, 3, 4, and intron 4 of the HLA-G gene were analyze d in 20 couples with habitual abortion, using polymerase chain reaction (PC R)-single-strand conformation polymorphism (SSCP) analysis. Intron 3 of the HLA-G gene was also analyzed in 54 healthy individuals. The nucleotide seq uence of the PCR product of intron 4 was further determined by direct seque ncing. RESULTS: Two kinds of nucleotide sequence were identified in intron 4 of th e HLA-G gene, one of which was identical to that of HLA-G*01011, and the ot her was identical to that of HLA-G*01012, G*01013, and G*0104. The frequenc y of each allele in affected women and their husbands did not significantly differ from that of healthy individuals, and no mutation was found in any affected couple. CONCLUSION: HLA-G allelic abnormality seemed to have little, if any, implic ation in the pathogenesis of habitual abortion.