Alper C A, Awdeh Z, Raum D, Yunis E J
Biochem Soc Symp. 1986;51:19-28.
The human major histocompatibility complex (MHC)-linked genes C2,BF,C4A,C4B occur in populations and segregate in families as single genetic units or complotypes. Analysis for significant three-point linkage disequilibrium between HLA-B, DR and complotype on normal caucasian chromosomes 6p yields about a dozen haplotypes that account for most of the known HLA-B/HLA-DR linkage disequilibrium pairs previously noted in normal caucasian populations. We refer to the HLA-B/DR/complotype sets with significant linkage disequilibrium as extended haplotypes since they often show limited variation at other MHC-linked loci. From the study of MHC haplotypes in 21-hydroxylase deficiency, C2 deficiency and type 1 diabetes, it is becoming apparent that it is extended haplotypes rather than their individual alleles that are markers for these MHC-associated diseases.
人类主要组织相容性复合体（MHC）相关基因C2、BF、C4A、C4B在人群中出现，并作为单一遗传单位或复合单型在家族中分离。对正常白种人6号染色体上HLA - B、DR与复合单型之间显著的三点连锁不平衡分析产生了大约一打单倍型，这些单倍型解释了先前在正常白种人群体中所观察到的大多数已知HLA - B/HLA - DR连锁不平衡对。我们将具有显著连锁不平衡的HLA - B/DR/复合单型组合称为扩展单倍型，因为它们在其他MHC相关位点通常显示出有限的变异。从对21 - 羟化酶缺乏症、C2缺乏症和1型糖尿病中MHC单倍型的研究来看，越来越明显的是，这些与MHC相关疾病的标志物是扩展单倍型而非其单个等位基因。
