Abstract
INTRODUCTION: B(3) is known to be one of the B subtypes that are characterized by serologic mixed-field agglutination. The proportion of Chinese Han individuals with the B(3) subtype (B type) and AB(3) subtype (AB type) is about 1/900 and 1/1,800, respectively. Here, we identified a novel ABO subgroup allele that caused B(3) phenotype. METHODS: The ABO phenotypes of the proband and his father were typed with the traditional test tube method. The ABO genotype was analyzed by SMRT sequencing. RESULTS: A c.122delG variant was identified in both the proband and his father, who exhibited the B(3) phenotype. This variation results in a premature stop codon, leading to mixed-field agglutination of the serological B antigen. CONCLUSION: The novel variation of c.122delG in the exon 3 of ABO*B3.0x allele were identified in Chinese individuals, resulting in mixed-field agglutination of B antigen expression and the formation of ABO subtypes.