C721T mutation of the α1,3 galactosyltransferase gene responsible for Bw subgroup


    To gain an insight into the molecular genetic basis of Bw subgroup of ABO blood group system.
    Three Bw phenotypes were confirmed by standard serological techniques. The enhancer, promoter and exons 1-7 including flanking introns of ABO gene were amplified and directly sequenced after PCR amplified fragments being purified by gel. Exons 6 and 7 were also sequenced after pcDNA3.1 (-) vector transformation. The sequence specific primer-polymerase chain reaction was performed to confirm the mutations detected by sequencing in this study.
    Genotypes of three individuals were Bw/O by direct sequencing, there were G deletion heterozygous at position 261 and C/T heterozygous at position 721. A normal O allele was confirmed by cloning sequencing and 721 C>T mutation of the alpha 1, 3 galactosyltransferase (B allele) gene was also observed, which caused amino acid 241 Arg>Trp substitution. This mutation was not detected in 140 random samples by PCR-SSP.
    The mutation of 721C>T in the alpha 1, 3 galactosyltransferase gene may be one of the molecular genetic bases of Bw phenotype.