摘要目的:探讨A205亚型个体的分子生物学及家系遗传特征。方法:选择2020年8月因术前血型筛查正反定型不符拟行进一步血型鉴定的1例先证者及其父母、弟弟为研究对象。先证者为男性，17岁。采用标准血型血清学方法对受试者进行ABO亚型鉴定，并且应用Sanger测序法确定 ABO基因突变情况。并且根据血清学和分子生物学检测结果，分析先证者血型在家系中的遗传特征。本研究经福建医科大学附属泉州第一医院伦理委员会批准(泉一伦[2021]124号)，受试者及家属均知情同意并签署知情同意书。 结果:① ABO血型鉴定结果显示，先证者及其母亲的血清学分型为Ax亚型， ABO基因分型为 A205/ O01，Sanger测序结果显示存在c.28+5859T>G、c.261delG、c.467C>T、 c.1009A>G。先证者父亲及弟弟的血清学分型为均O型。②家系调查结果显示，先证者与其母亲ABO血型分型、 ABO基因分型及测序结果一致，先证者的 ABO基因突变遗传自母亲。 结论:ABO基因 c.28+5859T>G单核苷酸突变可抑制 A基因的转录，而同时存在c.467C>T、c.1009A>G突变时，红细胞上A抗原表达减弱更为明显。

abstractsObjective:To investigate the molecular biology and genetic characteristics of A205 subgroup individuals.Methods:In August 2020, one patient who underwent further blood group identification due to positive and negative typing-discordant in blood screening before operation was admitted as a proband. And the proband, his parents and younger brother were selected as study subjects. This proband was a male, and 17 years old. Standard serological assay was carried out to identify ABO subtype and associated with Sanger sequencing to identify mutations of ABO gene. Based on results of serology and molecular biology, the genetic characteristics of proband′s blood group were analyzed. The procedures followed in this study were in accordance with the standards established by the Committee of Investigation in Human Beings of Quanzhou First Hospital Affiliated Fujian Medical University, and this study was approved by the committee (Approval No. [2021]124). All the subjects signed the informed consents for clinical trials. Results:① The blood group of proband and his mother was Ax subtype, genotype was A205/ O01, and results of Sanger sequencing were c. 28+ 5859T>G, c. 261delG, c. 467C>T, c. 1009A>G. The bloodgroup of proband′s father and brother was type O. ② According to pedigree analysis, the ABO blood group typing, ABO genotyping and sequencing results of proband were consistent with those of his mother. The ABO gene mutation of proband was inherited from mother. Conclusions:Mononucleotide mutation related to transcriptional regulation in ABO c. 28+ 5859 could inhibit transcription of A gene. While both c. 467C>T and c. 1009A>G existed simultaneously, the expression of A antigen in erythrocyte decreased more noticeably.