Analysis of the 14 bp insertion and deletion polymorphism in human leukocyte antigen‐G gene in two Chinese ethnic populations

Abstract

The biological significance of human leukocyte antigen-G (HLA-G) is now beyond its initial concepts on the fetal-maternal immune regulation. HLA-G in various pathophysical conditions has been investigated, such as autoimmunity, tumor, inflammation and transplantation. HLA-G has also been postulated as a chemotherapy response marker both in protein and in genetic contexts. In the current study, a total of 640 Chinese Han and 258 Chinese She ethnic minority populations had been genotyped for the 14 bp insertion (114 bp) and deletion (214 bp) polymorphism in the HLA-G gene. Significant difference was observed for both the 114 bp/114 bp (15.2% in the Han and 6.6% in the She; P ¼ 0.00048, P c ¼ 0.00097) and 214 bp/214 bp (34.5% in the Han and 50.4% in the She; P ¼ 1.05 Â 10 25 , P c ¼ 2.1 Â 10 25 ) genotypes between the two populations, and similar significance was found for both 114 bp (40.3% in the Han and 28.1% in the She) and 214 bp allele distributions (P ¼ 1.2 Â 10 26 , P c ¼ 2.4 Â 10 26 ). Furthermore, frequencies of the 14 bp genotype and alleles both in the Chinese Han and in the Chinese She populations were compared with other ethnic populations. Data showed that dramatic variations between different ethnic populations were also observed for this polymorphism. In summary, our results indicate that heterogeneity of the 14 bp polymorphism in the HLA-G gene among different ethnic populations is possibly the result of evolution.Recently, a 14 bp insertion/deletion polymorphism (rs16375) in exon 8 in the 3#-untranslated region (3#UTR) of the HLA-G gene has gained its interest. Studies indicated that the 14 bp insertion/deletion polymorphism was associated with HLA-G mRNA stability and isoform alternative splicing pattern and then influenced HLA-G mRNA expression or detection of soluble HLA-G (5-7). Functions of HLA-G in fetalmaternal immune maintenance had been well documented, suggesting that HLA-G serves as a protection factor for fetus from maternal allorecognition by modulating both the functions of immune component cells such as natural killer (NK) cells, T lymphocytes, antigen-presenting cells and the cytokine balance during pregnancy (8-11).

Linkage disequilibrium between HLA‐G*0104 and HLA‐E*0103 alleles in Tswa Pygmies

“…The frequency of the 14‐bp insertion in the French and Teke Congolese populations are close to the values ranging from 38.7% to 47.9% reported in various worldwide populations (7, 29, 36–40). These 14‐bp insertion values contrast sharply with the lower frequency observed in the Tswa Pygmy population, i.e.…”

Ethnic variation of the HLA‐G*0105N allele in two Chinese populations

“…In this Chinese She population, no copy of HLA‐G*0105N was found; furthermore, no HLA‐G*0105N homozygote was observed in Chinese Han population. In line with this, our previous study showed that the 14‐bp insertion/deletion polymorphism between these two populations also varied dramatically (13).…”

Distribution of HLA‐G 14‐bp insertion/deletion polymorphism in six Chinese ethnic groups

“… The data of 14‐bp insertion/deletion in Han‐FDYH, Han‐Zhejiang, She and Dai were published previously (Yan et al ., and Chen et al ., ). …”

“…The HLA‐G 14‐bp insertion/deletion frequencies and genotype counts for the currently studied six Chinese ethnic populations, and previously published four populations (Yan et al ., ; Chen et al ., ) are shown in Table and Fig. .…”

“…Yan et al . and our previous investigations on the distribution frequency of 14‐bp insertion/deletion in Han and other two ethnic groups (She and Dai) showed there were significant differences among these groups (Yan et al ., ; Chen et al ., ). Therefore, to investigate the genetic diversity of the HLA‐G 14‐bp insertion/deletion polymorphism in Chinese ethnic groups, we genotyped the 14‐bp insertion/deletion in six other Chinese ethnic groups, the Bulang, Wa, Hani, Jinuo, Maonan and Zhuang groups, which originated from three major ancient tribes, the Di‐Qiang, Baipu and Baiyue, and compared its frequency among them.…”