一例ABO血型系统Aw43亚型的基因突变研究

Study of the molecular basis of an individual with Aw43 subtype of the ABO blood group

目的研究1例AB0血型A亚型的分子机制。方法先证者及其家系成员（父母和姐姐）的AB0血型正反定型采用标准血清学技术。用PCR扩增先证者及其家系成员ABO基因的全部编码序列并进行双向测序分析。结果先证者红细胞与抗A呈现混合视野凝集，与抗B不凝集；其血清与A、0细胞均不凝集，与B细胞呈现凝集，血清学特性可定义为Aw亚型。ABO基因测序分析显示先证者1A／G、106G／T、188A／G、189C／T、220C／T、261G／del、297A／G、467C／T、646A／T、681A／G杂合。家系调查显示其母亲血清学表型特性和测序结果与先证者完全一致，其父亲基因型为B10I／002、姐姐为002／002。结合家系成员结果，可推断先证者AB0基因型中一个等位基因为002，另一个等位基因为新等位基因；它与A102相比存在1A＞G，导致起始密码子改变，已被红细胞血型基因数据库正式命名为Aw43。结论发现1例Aw43亚型，其α-1，3-N-乙酰半乳糖胺转移酶基因存在1A＞G和467C＞T变异。

Objective To explore the molecular basis of an individual with A subtype of the ABO blood group. Methods The ABO antigen and serum antibody of the proband and his parents and sister were detected by a serological method. The whole coding regions of the ABO gene were amplified by PCR and subjected to bidirectional sequencing. Results Red blood ceils of the proband showed mixed field agglutination with anti-A but did not agglutinate with anti-B, and his serum did not agglutinate with A and O cells but with B cells. The proband was identified as an Aw phenotype. Heterozygous status of 1A/G, 1060/T, 188A/G, 189C/T, 220C/T, 261G/del, 297A/O, 467C/T, 646A/T, and 681A/G of the coding region of the ABO gene were identified by directly sequencing of the proband. The serological characteristics and nucleotide sequences of the mother were similar to those of the proband. However, the ABO genotypes of his father and sister were B101/O02 and O02/O02. The proband therefore has carried an O02 allele and a novel allele. Compared with A102, the novel allele contains 1A〉G, which resulted in translation-initiator code change and was nominated as Aw43 by dbRBC of NCBI. Conclusion An Aw43 subtype has been identified for the first time, which may be attributed to the 1A〉G and 467C〉T variants on the α1, 3-N- acetyl-galaetosaminyltransferase gene.