Objective: To study the effect of 905A to G mutation of α -1,3 galactosyltransferase of ABO gene on B antigen expression.
Methods: Three samples were diagnosed as B subgroup by serological test. Genotyping and sequencing were performed with polymerase chain reaction-sequence specific primer (PCR-SSP), direct sequencing and gene dones of exons 6 and 7 of the ABO locus.
Results: The sequence of B allele has differed from that of regular B101 allele with a 905A to G missense mutation in exon 7, which resulted in an amino acid substitution (D302G) in all of the three B subgroup samples.
Conclusion: 905A to G mutation can reduce the expression of B antigen.