title: Frequent occurrence of conserved extended haplotypes (CEHs) in two Caucasian populations.
abstract: 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.
authors.affiliation: Research Group of Inflammation Biology and Immungenomics, Semmelweis University-Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Agnes
authors.initials: A
authors.lastname: Szilágyi
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Bánlaki
authors.forename: Eva
authors.initials: E
authors.lastname: Pozsonyi
authors.forename: Edmond J
authors.initials: EJ
authors.lastname: Yunis
authors.forename: Zuheir L
authors.initials: ZL
authors.lastname: Awdeh
authors.forename: Adrienn
authors.initials: A
authors.lastname: Hossó
authors.forename: Katalin
authors.initials: K
authors.lastname: Rajczy
authors.forename: Charles E
authors.initials: CE
authors.lastname: Larsen
authors.forename: Dolores A
authors.initials: DA
authors.lastname: Fici
authors.forename: Chester A
authors.initials: CA
authors.lastname: Alper
authors.forename: George
authors.initials: G
authors.lastname: Füst
mesh_terms: D001900:Boston; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics*; D005190:Family; D018628:Gene Dosage; D005838:Genotype; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D006814:Hungary; D008285:Major Histocompatibility Complex / Q000235:genetics*; D010375:Pedigree; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D044465:White People / Q000235:genetics