title: Distribution of MICA alleles and haplotypes associated with HLA in the Korean population.
abstract: The MICA (MHC class I chain-related gene A) is a polymorphic gene located 46 kb centromeric of the HLA-B gene, and is preferentially expressed in epithelial cells and intestinal mucosa. The MICA gene, similar to human leukocyte antigen (HLA) class I, displays a high degree of genetic polymorphism in exons 2, 3, 4, and 5, amounting to 54 alleles. In this study, we investigated the polymorphisms at exons coding for extracellular domains (exons 2, 3, and 4), and the GCT repeat polymorphism at the transmembrane (exon 5) of MICA in 199 unrelated healthy Koreans. Eight alleles were observed in the Korean population, with allele frequencies for MICA*010, MICA*00201, MICA*027, MICA*004, MICA*012, MICA*00801, MICA*00901, and MICA*00701 being 18.3%, 17.8%, 13.6%, 12.3%, 11.1%, 10.8%, 10.6%, and 3.3%, respectively. Strong linkage disequilibria were also observed between the MICA and HLA-B gene-MICA*00201-B58, MICA*004-B44, MICA*00701-B27, MICA*00801-B60, MICA*00901-B51, MICA*010-B62, MICA*012-B54, and MICA*027-B61. In the analysis of the haplotypes of HLA class I genes (HLA-A, B, and C) and the MICA, the most common haplotype was MICA*004-A33-B44-Cw*07, followed by MICA*00201-A2-B58-Cw*0302 and MICA*012-A2-B54-Cw*0102. The MICA null haplotype might be identified in the HLA-B48 homozygous individual. These results will provide an understanding of the role of MICA in transplantation, disease association, and population analyses in Koreans.
authors.affiliation: Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
authors.forename: Chul-Woo
authors.initials: CW
authors.lastname: Pyo
authors.forename: Seong-Suk
authors.initials: SS
authors.lastname: Hur
authors.forename: Yang-Kyum
authors.initials: YK
authors.lastname: Kim
authors.forename: Hee-Baeg
authors.initials: HB
authors.lastname: Choi
authors.forename: Tae-Yoon
authors.initials: TY
authors.lastname: Kim
authors.forename: Tai-Gyu
authors.initials: TG
authors.lastname: Kim
mesh_terms: D005787:Gene Frequency; D006239:Haplotypes; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D007723:Korea / Q000453:epidemiology; D018911:Trinucleotide Repeats
chemical_list: D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A