[Serological feature and molecular mechanism for a case with A307 subgroup].

OBJECTIVE

To explore the serological feature and molecular mechanism for a case with A307 subgroup of the ABO blood group system.

METHODS

Serological assay was carried out to determine the ABO blood group of the proband and his family members. Genotypes for exons 1 to 7 of the ABO gene were determined with sequence-specific primer polymerase chain reaction (SSP-PCR) and direct sequencing. The impact of the variant on the stability of alpha-1,3-N-acetylgalactosaminyltransferase (GTA) was predicted through construction of a 3D molecular model.

RESULTS

The proband, his brother and daughter were diagnosed with Aend phenotype by serological analysis. Their ABO genotype was determined as A307/O02, with heterozygous c.467C>T (p.P156L) and c.745C>T (p.R249W) variants identified in exon 7 of the ABO gene. Molecular modeling suggested that the p.R249W variant may alter the number of hydrogen bonds between the amino acids. The protein was predicted to have a decreased Δ Δ G value of thermodynamic stability.

CONCLUSION

The p.R249W variant may give rise to the A307 subgroup by reducing the stability of the GTA enzyme, leading to serological features of Aend phenotype.