A novel FYA allele with the 265T and 298A SNPs formerly associated exclusively with the FYB allele and weak Fy(b) 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: England 01-01-2015
• Subjects: Algorithms; Alleles; Australia; Blood Donors; Duffy Blood-Group System - genetics; European Continental Ancestry Group - genetics; Genotype; Genotyping Techniques - methods; Humans; Molecular Sequence Data; Phenotype; Polymorphism, Single Nucleotide; Australia; novel FYA allele; Duffy blood group; reduced Fya expression; FY01W.02
• ISSN: 1423-0410
• DOI: 10.1111/vox.12185

An Australian Caucasian blood donor consistently presented a serology profile for the Duffy blood group as Fy(a+b+) with Fy(a) 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.
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.
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.
The reduced Fy(a) 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 Fy(b) antigen expression. This novel allele should be considered in genotyping interpretative algorithms for generating a predicted phenotype.