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

Unlike high polymorphic classical human leukocyte antigen (HLA) class I molecules, the genetic polymorphism of HLA-G is very limited. However, the prevalence of HLA-G alleles among different ethnic populations varied dramatically. The HLA-G null allele (HLA-G0105N) is defined by a cytosine deletion (Delta C) at position 1597 in exon 3, which disrupts the reading frame and alters the expression of HLA-G proteins. The HLA-G0105N allelic frequency was investigated in previous studies and possible roles were addressed. In the current study, a total of 310 Chinese Han and 260 Chinese She ethnic minority population had been genotyped for the G0105N polymorphism. Marked difference was observed that the G0105N allelic frequency in Chinese Han was 1.61%, while no copy of the null allele was observed in the Chinese She minority population (P(c) = 0.0073). Data also revealed that no homozygote of HLA-G0105N allele exists in this Chinese Han population. Furthermore, significant difference was found for the frequencies of HLA-G0105N both in Chinese Han and in Chinese She populations when compared with other ethnic populations. Taken together, our results indicated that ethnic variation of the HLA-G*0105N polymorphism among different ethnic populations is possibly the result of evolution. However, the advantages of the selection of this allele are necessary to be further investigated.