Genetic sequencing analysis of the A307 subgroup of ABO blood group.

The aim of this study was to investigate the serology and gene sequence characteristics of the A307 subgroup of ABO blood group. Monoclonal anti-A and anti-B antibodies were used to detect the ABO antigens of a proband whose positive blood type was not consistent with the negative blood type of ABO blood group. Meanwhile, standard A-, B-, and O-negative typing cells were used to test for ABO antibodies in the serum. Additionally, polymerase chain reaction with sequence-specific primer (PCR-SSP) was used to confirm the genotype, and subsequently, exons 6 and 7 of the ABO gene were detected by gene sequencing. Samples from the wife and daughters of the proband were also used for serological and genetic testing. Red blood cells of the proband showed weak agglutination reaction with anti-A antibody, while anti-B antibody was detected in the serum. Moreover, PCR-SSP detected A307 and O02 alleles, while gene sequencing revealed mutation of c.745C>T in exon 7, which produced a polypeptide chain p.R249W. Furthermore, the A307 gene of the proband was not inherited by his daughters. A mutation (c.745 C>T) in exon 7 of the ABO blood group gene resulted in low activity of α-1, 3-N-acetyl-galactosaminyl transferase, producing A3 phenotype.