摘要目的:探讨cisAB亚型先证者的血型血清学及分子生物学特征，并对其家系进行调查。方法:选择2020年11月于宝鸡市中心血站参加无偿献血的1例ABO血型正反定型不符献血者为先证者，并选择其父亲(43岁)、母亲(40岁)、弟弟(15岁)、妹妹(16岁)，共同纳入本研究。本例先证者为18岁、女性；先证者及其家系成员均为汉族，身体健康且无家族遗传病史。采用试管法对受试者全血标本进行血型血清学检测。对ABO血型正反定型结果不一致的标本，采用 ABO基因第6、7外显子扩增后直接测序，进行血型分子生物学检测。并且根据血型鉴定结果对受试者的血型基因进行家系分析。本研究遵循的程序符合2013年修订版《世界医学会赫尔辛基宣言》要求，并且与所有受试者签署知情同意书。 结果:①本组受试者血型血清学检测结果显示，先证者及其父亲和妹妹均为cisAB亚型，先证者母亲和弟弟为O型。cisAB亚型家系成员的血型血清学特征为B抗原弱表达，血清中同时存在抗-A、抗-B。②先证者及其父亲、妹妹ABO血型分子生物学检测结果提示，其 ABO基因第7外显子存在c.297A>G、c.526C>G、c.657C>T、c.703G>A、c.803G>C、c.930G>A杂合突变和c.796A>C回复突变；产生cisAB亚型新等位基因 ABO*cisABnovel(OM628853)。③家系调查结果显示，先证者及其妹妹的 ABO*cisABnovel等位基因遗传自其父亲。 结论:先证者家系中，cisAB亚型 ABO*cisABnovel等位基因稳定遗传，并导致B抗原的弱表达，产生抗-B免疫反应。

abstractsObjective:To explore the blood group serological and molecular biological characteristics of one proband with cisAB subtype and investigate her pedigree.Methods:A blood donor with inconsistent forward and reverse typing of ABO blood group who participated in voluntary blood donation at Baoji Central Blood Station in November 2020 was selected as the proband, and her father (43 years old), mother (40 years old), younger brother (15 years old), and younger sister (16 years old) were selected and included in this study. The proband in this study was an 18-year-old female. The proband and her family members were all Han nationality, in good health, and had no family history of genetic diseases. Whole blood specimens from all subjects were tested for ABO blood group serology identification using the test-tube method. For the specimens with inconsistent forward and reverse typing of ABO blood group, blood group molecular biological identification was performed by amplifying the 6 and 7 exons of the ABO gene and then directly sequencing them. According to the blood group identification results, the blood type gene of subjects was analyzed in the family. This study was in line with World Medical Association Declaration of Helsinki revised in 2013, and informed contents were obtained from the subjects. Results:① The results of blood group serological testing of subjects in this study showed that the proband, her father and sister were all cisAB subtype, and the proband′s mother and brother were O type. The blood group serological characteristics of family members with cisAB subtype are weak expression of the B antigen and the presence of both anti-A and anti-B in the serum. ② The results of ABO blood group molecular biology testing of the proband, her father and sister indicated that there were heterozygous mutations at c. 297A>G, c.526C>G, c. 657C>T, c. 703G>A, c. 803G>C, c. 930G>A and reversion mutation at c. 796A>C in exon 7 of their ABO gene, resulting in the cisAB subtype novel allele ABO*cisABnovel (OM628853). ③ The results of pedigree investigation showed that the proband and his sister inherited the ABO*cisABnovel allele from their father. Conclusions:In the proband′s family, the cisAB subtype ABO*cisABnovel allele was stably inherited and resulted in weak expression of B antigen and anti-B immune response.