[C721T mutation of the alpha 1,3 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.