Objective: To explore the molecular basis for an A subtype of the ABO blood group.
Methods: The forward and reverse typing of the ABO blood group were identified by gel card and test tube methods. The ABO gene of the patient was detected by PCR-sequence specific primer (PCR-SSP). Exons 1 to 7 of the ABO gene was amplified by PCR and sequenced. The ABO gene was also subjected to subclone sequencing for haplotype analysis.
Results: The patient's red cells showed weak agglutination with anti-A but non-agglutination with anti-B. The patient's serum showed 1+ agglutination with A cells and 4+ agglutination with B cells. Based on above serological characteristics, the patient was defined as Aw subtype of the ABO blood group. Sequencing analysis showed that the patient was heterozygous for c.106G>T, c.188G>A, c.189C>T, c.220C>T, c.297A>G, c.467C>T, c.543G>C, c.646T>A, c.681G>A, c.771C>T, c.829G>A, in addition with a c.261G deletion. Combined with the result of subclone sequencing, the ABO genotype of the patient was determined as ABO*AW.33. new/O.01.02, which harbored c.467C>T and c.543G>C variants compared with ABO*A1.01 and c.543G>C variant compared with ABO*A1.02. The novel allele has been submitted to GenBank with an accession number of MK302122.
Conclusion: A novel allele of Aw33 subtype has been identified with its GTA transferase gene harboring c.467C>T and c.543G>C variants compared with A1.01.