目的:通过对一例ABO亚型家系血清学和基因序列分析，研究该家系中α-1，3- N-乙酰半乳糖胺基转移酶基因新变异位点的特征。方法:收集先证者及其3名家系成员血液标本，血清学方法进行ABO表型检测，荧光PCR进行ABO血型基因分型。通过对先证者ABO基因全编码区直接测序及第6、7外显子克隆测序方法进行基因序列及单体型分析。结果:先证者血型为AxB亚型，ABO血型基因分型为A/B。克隆测序结果显示A新等位基因在n ABO*n A1.02序列基础上存在第7外显子c.797_798 insT变异。家系调查发现，先证者及其姐姐新变异均遗传自其父亲。c.797_798insT新变异序列已注册基因数据库(MK125137)。n 结论:α-1，3- N-乙酰半乳糖胺基转移酶基因第7外显子c.797_798insT新变异为可遗传变异，可导致A抗原表达减弱。“,”Objective:To explore the genetic basis for a Chinese pedigree with a novel ABO subtype.Methods:The proband and his family members were subjected to serological analysis, and their genotypes were determined by fluorescence PCR and direct sequencing of the coding regions of the n ABO gene. Exons 6 to 7 of the n ABO gene were also subjected to clone sequencing for haplotype analysis.n Results:The proband was determined as an AxB subtype. By fluorescence PCR, he was typed as A/B. Clone sequencing has revealed a insertional mutation c. 797_798 insT in exon 7 of the n ABO gene, which yielded a novel allele. Pedigree analysis confirmed that the novel ABO*A1.02 allele carried by the proband and his sister were inherited from their father. The c. 797_798insT mutation has been submitted to GenBank with an accession number of MK125137.n Conclusion:The c. 797_798insT mutation of exon 7 of the n ABO gene probably has led to weakened expression of A antigen.n