title: The study of the extended haplotypes of rare HLA-B*2730 allele using microsatellite loci.
abstract: The aim of the present study was to compare haplotypes of the most frequent B*27 alleles among Croatians (B*2702 and *2705) and the rare B*2730 allele. For this purpose, 37 families with members carrying human leukocyte antigen (HLA)-B27 were selected. All individuals were analysed for eight microsatellites (Msats): D6S2927, short tandem repeat - MHC class I-related gene (STR_MICA), D6S2793, D6S2811, tumor necrosis factor a (TNFa), tumor necrosis factor d (TNFd), D6S273 and D6S1014, while individuals carrying the HLA-B27 specificity were subtyped. Of 39 analysed haplotypes, 20 individuals had B*2702, 15 subjects were positive for the B*2705 allele, the B*2730 allele was found in three haplotypes from different families, while one individual carried the B*2703 allele. HLA-A3 and -DRB1*16 were shared by all three B*2730 haplotypes. The DRB1*16 allele was also observed in the majority of B*2702 haplotypes (76.5%), while HLA-A3 was, after HLA-A2, the second most frequent HLA-A specificity in B*2702 haplotypes. No such correlation was found for the B*2705 haplotypes. Msat analysis showed that B*2730 haplotypes also share the same allele at all tested Msats. The D6S2927, D6S2793, MICA and TNFd Msats were not useful in distinguishing B*2702 and B*2705 alleles because D6S2927-213bp, STR_MICA-179bp, D6S2793-206bp, D6S2811-83bp and TNFd-130bp were detected in almost all cases. Conversely, for the TNFa, D6S273 and D6S1014 loci, haplotypes carrying B*2702 and B*2730 shared a single Msat allele in the majority of cases (TNFa-113bp, D6S1014-134bp and D6S273-134bp), which was not observed for B*2705 haplotypes. In conclusion, the similarity between B*2702 and B*2730 DNA sequences as well as their sharing of the same haplotypic combinations corroborates the proposed mechanism of B*2730 evolution from B*2702 by interallelic recombination.
authors.affiliation: University Hospital Centre, Zagreb, Croatia. zgrubic@kbc-zagreb.hr
authors.forename: Z
authors.initials: Z
authors.lastname: Grubić
authors.forename: K
authors.initials: K
authors.lastname: Stingl
authors.forename: V
authors.initials: V
authors.lastname: Kerhin-Brkljacić
authors.forename: R
authors.initials: R
authors.lastname: Zunec
mesh_terms: D000483:Alleles; D017523:Croatia; D019143:Evolution, Molecular; D005190:Family; D005260:Female; D015791:HLA-A3 Antigen / Q000235:genetics; D015235:HLA-B Antigens / Q000235:genetics*; D015796:HLA-B27 Antigen; D006684:HLA-DR Antigens / Q000235:genetics; D059811:HLA-DRB1 Chains; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D040641:Quantitative Trait Loci / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics
chemical_list: D015791:HLA-A3 Antigen; D015235:HLA-B Antigens; C464936:HLA-B*27:05 antigen; C515025:HLA-B*27:30 antigen; D015796:HLA-B27 Antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains