中国人群ABO亚型中一个新的Ax等位基因的鉴定  

Identification of a novel Ax allele through a nucleotide substitution 426G>C

作　　者：蔡晓红[1] 金沙[1] 刘曦[1] 王健莲[1] 陆琼[1] 沈伟[1] 范亮峰[1] 刘达庄[1] 向东[1] 

机构地区：[1]上海市血液中心上海市输血研究所检测中心血型参比实验室,上海200051

出　　处：《临床血液学杂志（输血与检验）》2009年第3期309-312,共4页Journal of Clinical Hematology(Blood Transfusion & Laboratory Medicine)

摘　　要：目的Ax是一种罕见的ABO亚型,其分子机理尚未完全阐明。本文以一个Ax亚型家系和一个无关的Ax亚型献血者个体为对象,研究中国人群Ax亚型的分子基础。方法ABO血清学定型、血浆N-乙酰-D-半乳糖胺基转移酶(A酶)活性测定、ABO基因7个外显子及其侧翼序列的PCR扩增、基因克隆和测序分析。结果DNA克隆和测序分析显示,家系先证者和无关献血者个体的ABO基因分别为A/O01和A/O02基因型,在第7外显子均存在426G>C杂合突变,导致N-乙酰-D-半乳糖胺基转移酶的氨基酸发生M142I改变。在120个正常样本中未检出此突变。结论ABO基因426G>C突变导致的N-乙酰-D-半乳糖胺基转移酶第142位氨基酸置换改变了酶的保守区域,从而降低了酶的催化活性,导致Ax表现型。本突变为国际首次报道。Objective：As is a very rare ABO blood group phenotype and the molecular mechanism underlying it still remains largely unknown. In this study, we studied the molecular basis of Ax subgroup in Chinese population by a Ax Chinese family and an unrelated Ax Chinese donor. Method：Serologic investigations were performed including serum transferases activity assay. DNA sequences of all 7 exons and exon-intron boundaries of ABO gene were analyzed using genomie DNA by polymerase chain reaction （PCR） and direct DNA sequencing or sequencing after gene cloning. Result：DNA analysis revealed that the ABO gene of the proband and the unrelated donor were heterozygous of A/O01 and A/O02 alleles. A novel mutation 426G〉C was identified in A allele, which resulted in the amino acid changes M142I in the A glycosyltransferase. Conclusion：Amino acid substitutions resulted from novel mutations 426G〉C on ABO gene change highly conserved regions of the enzyme and may reduce the activity of the glyeosyltransferases, leading to the Ax phenotype.

关 键 词：Ax等位基因 ABO基因 血型 亚型 

分 类 号：R457.1[医药卫生—治疗学]