两例ABO变异型Bw亚型的分子遗传学分析

Molecular genetic analysis of two individuals with Bw subtypes of ABO variant

目的研究ABO变异型Bw亚型的分子生物学特性。方法通过标准血型血清学方法鉴定2例Bw亚型，采用聚合酶链反应一序列特异性（polymerasechainreactioIsequencespecificprimer，PCR-SsP）技术进行ABO基因分型，特异性扩增B基因第6～7外显子，PCR产物纯化后直接测序分析。结果血清学鉴定2例Bw亚型，PCR-SSP结果显示样本基因型为B／（）2。B基因直接测序结果发现1例与B101序列比对第7外显子存在721C〉T突变，导致多肽链R241S替换；另1例与B101比对第6外显子存在278C〉T突变，导致多肽链P93L替换。结论发现Bw03、Bw12亚型各1例，其表达B抗原的强弱存在差异。

Objective To investigate the molecular characteristics of Bw subgroup of ABO variant. Methods Two individuals with Bw phenotypes were confirmed by standard serological assays. ABO genotype was analyzed with polymerase chain reaction-sequence specific primer （PCR-SSP） method. Exons 6-7 of B genes were amplified by specific PCR, and the PCR product was subjected to direct sequencing. Results The probands were identified as Bw phenotype by serological assays. As detected by PCR-SSP, the genotypes of the two probands were both B/O2. Compared with the wild-type B101, the B allele in one individual has harbored a missense mutation （C721T） in exon 7, which resulted in an amino acid substitutions （R241S）. In the second individual, the B allele has harbored a missense mutation （C278T） in exon 6, which also resulted in an amino acid substitution （P93L）. Conclusion A Bw03 allele and a Bw12 allele were identified, which resulted in varied intensity of B antigen expression.