[Identification and pedigree analysis for an A(W)37B subtype due to c.940A>G variant of ABO gene]

To delineate the serological and molecular profiles of a patient with A(w)37B subtype.

The ABO bloodtypes of the proband, his wife and daughter were determined with a standard serological method. Their ABO genotypes were determined by sequence-specific primer polymerase chain reaction (PCR-SSP). All exons of the ABO gene were directly sequenced. Exons 6 and 7 of the ABO gene were further analyzed by cloning and sequencing.

The red blood cells of the proband showed a weak B phenotype. His serum sample contained weak reactive anti-A antibody, which was defined as A(w)B blood group based on the serological characteristics. The A and B alleles were detected by blood group genotyping. Gene cloning and sequencing have identified a characteristic c.940A>G variant (ABO*AW.37) in exon 7 of the ABO gene, which resulted in substitution of Lysine by Glutamate at position 314. The proband's daughter has inherited the ABO*AW.37 allele.

The c.940A>G variant in exon 7 of the ABO gene probably underlay the decreased activity of GTA transferase and resulted in the Aw37 phenotype.