OBJECTIVETo investigate the molecular genetic basis of the Bw variant and identify novel alleles at ABO locus in Chinese Han population.

METHODSSerological techniques were performed to characterize erythrocyte phenotype of a proband. Mutations of the ABO gene were screened by polymerase chain reaction, reverse transcription-polymerase chain reaction and DNA sequencing.

RESULTSThe proband was identified as Bw phenotype by serological technology and family study. A novel Bw variant allele was identified in the gDNA and cDNA. The novel allele was observed a missense mutation (278 C to T) at the exon 6 which resulted in an amino acid substitution (P93L) compared with B101 allele. The 278 C to T was the first report mutation position in exon 6 among Bw alleles, so the P93L amino acid substitution was different from others Bw variants which had amino acid substitutions in a conserved functional domain reported previously.

CONCLUSIONA novel Bw allele (278 C to T) responsible for Bw variant is reported in Chinese population.