Identify a Novel ABO Allele Similar to ABO*AW.41 Allele with Additional c. 467C>T

Accurate identification of the ABO blood group is of great significance in ensuring the safety of clinical blood transfusions. Using molecular technologies combined with serological testing helps to identify the new ABO variants.

The traditional serological blood type test was performed for a 4-year-old Chinese boy, and the result showed a weaker agglutination with anti-A reagent (3+ strength by microcolumn gel card method; 2+ strength by saline tube method). A molecular genotyping assay was performed to get more information.

The ABO gene sequence study indicated two heterozygous nucleotide sites: c.370A>G (p.Lys124Glu) in exon 6 and c.467C>T (p.Pro156Leu) in exon 7, and ABO*B.01 mutations. Further single-strand sequencing analysis showed that the mutation sites were located in gene A. The individual c.467T variant was unique to the ABO*A1.02 allele, while the c.370A>G was not found in the known ABO*A1.02 allele. The individual c.370A>G mutation was characteristic of ABO*AW.41 (previously also known as Ax17), but the ABO*AW.41 allele did not contain the c. 467C>T mutation.

A novel A allele with c.370A>G in the ABO*A102 allele or ABO*AW.41 with c.467C>T was identified, leading to a weak A phenotype.