[Serological and molecular study of three cases with a rare Bx02 blood group]

To determine the genotypes of three blood samples suspected as B subtype through DNA sequencing.

The samples were first genotyped with PCR-SSP. Exons 6 and 7 of the ABO genes were subjected to PCR, direct sequencing, and cloned sequencing to determine the genotypes.

Serological results of the three samples were similar, with red cells being weakly agglutinatable by anti-B and serum containing anti-B. The samples were preliminarily genotyped as B/O1. Sequencing analysis showed that all three samples contained an O allele and a 905A>G mutation of the B gene, which was previously defined as Bx02.

Through sequencing analysis, the three samples typed as B subtype with serological testing were identified as Bx phenotype. The genotype of samples 1 and 2 was Bx02/O101, and that of sample 3 was Bx02/O102.