A novel FYA allele with the 265T and 298A SNPs formerly associated exclusively with the FYB allele and weak Fyb antigen expression: implication for genotyping interpretative algorithms

• Published in: Vox sanguinis Vol. 108; no. 1; pp. 52 - 57
• Main Authors: Lopez, G. H., Condon, J. A., Wilson, B., Martin, J. R., Liew, Y.-W., Flower, R. L., Hyland, C. A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Blackwell Publishing Ltd 01-01-2015; S. Karger AG
• Subjects: Algorithms; Antigens; Blood & organ donations; Duffy blood group; FY01W.02; Genes; Hematology; novel FYA allele; reduced Fya expression
• ISSN: 0042-9007; 1423-0410
• DOI: 10.1111/vox.12185

Background and Objectives
An Australian Caucasian blood donor consistently presented a serology profile for the Duffy blood group as Fy(a+b+) with Fya antigen expression weaker than other examples of Fy(a+b+) red cells. Molecular typing studies were performed to investigate the reason for the observed serology profile.
Material and Methods
Blood group genotyping was performed using a commercial SNP microarray platform. Sanger sequencing was performed using primer sets to amplify across exons 1 and 2 of the FY gene and using allele‐specific primers.
Results
The propositus was genotyped as FY*A/B, FY*X heterozygote that predicted the Fy(a+b+w) phenotype. Sequencing identified the 265T and 298A variants on the FY*A allele. This link between FY*A allele and 265T was confirmed by allele‐specific PCR.
Conclusion
The reduced Fya antigen reactivity is attributed to a FY*A allele‐carrying 265T and 298A variants previously defined in combination only with the FY*B allele and associated with weak Fyb antigen expression. This novel allele should be considered in genotyping interpretative algorithms for generating a predicted phenotype.