title: HLA-G polymorphisms and allele frequencies in Caucasians.
abstract: HLA-G, a nonclassical class I MHC molecule, is uniquely expressed on extravillous cytotrophoblasts of the maternal-fetal interface and is suggested to be essential for establishment of maternal-fetal immune tolerance. Although the level of polymorphism in HLA-G has originally been considered low, number, nature and site of polymorphisms seem to vary between different ethnic populations. We investigated HLA-G polymorphisms in a population of German and Croatian origin by SSCP-analysis and direct sequencing as well as RFLP analysis for presence of the 1597delC mutation. HLA-A alleles associated with the different HLA-G alleles were determined by SSP PCR-typing. In Caucasians, HLA-G exhibits a low degree of polymorphism on the amino-acid level and only slightly higher variability on the nucleotide level. In 264 independent chromosomes, 4 HLA-G alleles on the level of amino acid polymorphisms and an additional 6 variations of nucleotide sequences could be identified. The null-allele G*0105N was present at an allele frequency of 2.3%, which is higher than initially suggested for Caucasians but lower than in Hispanics and African-Americans. Furthermore, some HLA-G alleles exhibit strong linkage disequilibrium with HLA-A.
authors.affiliation: University of Bonn, Department of Obstetrics and Gynecology, Germany.
authors.forename: K
authors.initials: K
authors.lastname: van der Ven
authors.forename: S
authors.initials: S
authors.lastname: Skrablin
authors.forename: G
authors.initials: G
authors.lastname: Engels
authors.forename: D
authors.initials: D
authors.lastname: Krebs
mesh_terms: D000328:Adult; D000483:Alleles; D002648:Child; D005260:Female; D006680:HLA Antigens / Q000235:genetics*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D009154:Mutation; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics; D016415:Sequence Alignment; D044465:White People / Q000235:genetics*
chemical_list: D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I