ABO亚型B(A)的鉴定及其分子机制研究

Identification and molecular mechanism of ABO subtype B(A)

目的探讨ABO亚型B(A)的血型鉴定方法及其分子机制。方法选择2015年7月,于山东省泰安市中心医院因ABO血型正反定型不符,拟行进一步血型鉴定的1例患者为先证者;以先证者、先证者丈夫及其2个儿子为研究对象。本例先证者为女性,45岁。采用常规血清学方法鉴定受试者的ABO血型。采用序列特异性引物(SSP)-PCR法对受试者ABO基因第6、7外显子进行直接测序,并且根据测序结果确定其ABO基因型。本研究遵循的程序符合山东省泰安市中心医院人体试验委员会制定的标准,经过该伦理委员会批准(批准文号:2015-018),并与所有受试者签署临床研究知情同意书。结果①ABO血型正反定型检测结果显示,先证者及其长子ABO血型为B(A)亚型,先证者丈夫和次子为O型。吸收放散试验结果显示,先证者与其长子血清标本中检测出A抗原,其丈夫与次子未检测出A抗原。②ABO基因测序结果显示,先证者及其长子均检出O02等位基因,ABO基因第7外显子存在c.640A>G突变,符合B(A)04等位基因的特征,其基因型均为B(A)04/O02;先证者丈夫和次子基因型为O01/O02。先证者长子的B(A)04等位基因来源于先证者,B(A)04等位基因的遗传方式为顺式遗传。结论分子生物学方法是鉴定罕见ABO亚型的必要方法。ABO基因第7外显子c.640A>G突变是形成B(A)04等位基因的分子遗传学基础之一。

Objective To explore the blood group identification method of ABO subtype B(A)and its molecular mechanism.Methods In July 2015,a patient who planned to conduct further blood group identification due to the inconsistent of ABO blood group positive and negative determination at the Taian Central Hospital in Shandong Province,was selected as the proband.This proband,her husband and 2 sons were selected as study subjects.This proband was female,and 45 years old.The ABO blood groups of all subjects were identified by serological methods.Sequence specific primer(SSP)-PCR was used to directly sequence the exon 6 and 7 of the subjects′,ABO gene,and their ABO genotypes were determined based on the sequencing results.The procedures followed in this study were in accordance with the standards established by the Medical Ethics Committee of Taian Central Hospital,and this study was approved by the committee(Approval No.2015-018).All the subjects signed the informed consents for clinical trials.Results①Results of ABO blood type positive and negative determination showed that the ABO blood groups of proband and her eldest son were B(A)subtype,and that of her husband and younger son were O type.Results of absorption and release test showed that A antigen was detected in the serum samples of the proband and her eldest son,but the A antigen was not detected in serum samples of her husband and the younger son.②The gene sequencing results of the proband and her elder son indicated an O02 allele and a nucleotide mutation at c.640A>G in exon 7 of ABO gene,which was in accordance with the characteristic of B(A)04 allele,and the genotype was B(A)04/O02.The genotype of proband′s husband and the younger son was O01/O02.The B(A)04 allele of her elder son was come from his mother.The inheritance of B(A)04 allele was cis.Conclusions The method of molecular biology is necessary for identifying rare ABO subtypes.The c.640A>G mutation on exon 7 of ABO gene is the genetic basis of B(A)04 allele.