摘要
目的研究1例ABO血型系统ABx变异型的分子遗传背景。方法用血型血清学技术鉴定1例AB0血型疑难样本的红细胞表型和唾液血型分泌物质，并用聚合酶链反应分别扩增先证者ABO基因全编码区共7个外显子及侧翼内含子序列，扩增产物经双酶切纯化后直接进行双向测序分析。进一步对存在突变位点的第6～7外显子扩增产物经进行TA克隆和单倍体序列分析。结果先证者红细胞ABO抗原表达为A强B弱，结合其它血清学特征，鉴定其血型为罕见的ABx变异型。ABO基因全编码区测序发现9处核苷酸杂合位点，分别为第6外显子的297A／G杂合，第7外显子的467C／T、526C／G、657C／T、703G／A、796C／A、803G／C、808T／A、930G／A杂合。单倍体序列分析发现，其中一个等位基因为常见的A102，另一个等位基因除808T〉A突变外，其它变异位点与B101等位基因一致。808T〉A突变可导致B糖基转移酶第270位苯丙氨酸转变为异亮氨酸。结论B糖基转移酶基因808T〉A突变可能引起酶活性减弱，并进而导致产生Bx变异型。
Objective To explore the molecular basis of an individual featuring an ABx variant of ABO blood group system. Methods Serological assays were used to characterize the erythroeyte phenotypes and salivary ABH secretors. All of the seven exons and flanking introns of ABO glycosyltransferase gene were amplified with polymerase chain reaction （PCR）. And the products were sequenced bidirectionally following enzyme digestion. Exons 6 and 7 were also subeloned and analyzed for haplotypes of the ABO gene. Results Erythrocytes of the proband have expressed a strong A antigen and a weak B antigen, which was identified as a rare ABx variant in addition with other serological features. Nine heterozygous sites in exon 6 （297A/G） and exon 7 （467C/T, 526C/G, 657C/T, 703G/A, 796C/A, 803G/C, 808T/A, 930G/ A） of the coding region of the ABO gene were identified. Based on haplotype analysis, one allele was determined as common A102, whilst another was consistent with B101 except for an 808T〉A mutation which has resulted in replacement of phenylalanine with isoleueine at position 270 of glycosyltransferase B. Conclusion The 808T〉A mutation of the glycosyltransferase B gene may decrease the enzymatic activity and result in the Bx variant.
出处
《中华医学遗传学杂志》
CAS
CSCD
北大核心
2012年第5期566-569,共4页
Chinese Journal of Medical Genetics
基金
国家自然科学基金（30871112）
浙江省自然科学研究基金（Y2101289）
浙江省卫生高层次创新人才培养工程项目
