Research Group of Inflammation Biology and Immungenomics, Semmelweis University-Hungarian Academy of Sciences, Budapest, Hungary.
Mol Immunol. 2010 Jun;47(10):1899-904. doi: 10.1016/j.molimm.2010.03.013. Epub 2010 Apr 20.
Conserved extended haplotypes (CEHs) are large (>or=1Mb) regions of identical DNA of the major histocompatibility complex (MHC) region of chromosome 6p in unrelated individuals. They are recognized by family studies and constitute nearly half of MHC haplotypes among European Caucasians. We studied 49 Hungarian Caucasian families in comparison with the previous findings in 2675 normal American Caucasian chromosomes from families in the Boston area. Besides HLA-A, -B and HLA-DRB1/-DQB1 alleles, copy number polymorphism of C4A and C4B genes and several SNPs encoded in the central (class III) MHC region were determined. By comparing 188 Caucasian haplotypes in Hungary to 2675 normal Caucasian chromosomes in Boston, we found that 11 of 12 of the most common CEHs (with a frequency of at least 1%) among the Boston chromosomes also occurred in Hungary. Moreover, there was a significant correlation (R=0.789; p=0.0023) in the frequency order of these haplotypes between the two Caucasian populations. Of 10 haplotypes found in >or=2 copies among the Hungarian chromosomes, all but one occurred in one to 14 copies among the Boston haplotypes. These findings indicate that CEHs are commonly shared by distinct European Caucasian populations; however, lower frequency CEHs may differ.
保守延伸单倍型（CEHs）是 6p 染色体主要组织相容性复合体（MHC）区域中大于或等于 1Mb 的相同 DNA 大片段，在无亲缘关系的个体中被家族研究识别，并且构成欧洲白种人 MHC 单倍型的近一半。我们研究了 49 个匈牙利白种人家系，并与之前在波士顿地区家系中 2675 个正常美国白种人染色体的研究结果进行了比较。除了 HLA-A、-B 和 HLA-DRB1/-DQB1 等位基因外，还确定了 C4A 和 C4B 基因的拷贝数多态性以及中央（III 类）MHC 区域中几个 SNP 的编码。通过比较匈牙利的 188 个白种人单倍型和波士顿的 2675 个正常白种人染色体，我们发现 12 个最常见的 CEHs（在波士顿染色体中的频率至少为 1%）中有 11 个也发生在匈牙利。此外，这两个白种人群体中这些单倍型的频率顺序存在显著相关性（R=0.789;p=0.0023）。在匈牙利染色体中发现的 10 个存在于 2 个以上拷贝的单倍型中，除了一个之外，其余都存在于波士顿单倍型的 1 到 14 个拷贝中。这些发现表明 CEHs 在不同的欧洲白种人群体中普遍共享；然而，低频 CEHs 可能存在差异。
