<abstract xmlns="http://www.w3.org/1999/xhtml">Duffy antigens are important in immunohematology. The reference allele for the Duffy gene <italic>(FY)</italic> is <italic>FY*02,</italic> which encodes Fyb. An A>G single nucleotide polymorphism (SNP) at coding nucleotide (c.) 125 in exon 2 defines the <italic>FY*01</italic> allele, which encodes the antithetical Fya. A C>T SNP at c.265 in the <italic>FY*02</italic> allele is associated with weakening of Fyb expression on red blood cells (RBCs) (called FyX). Until recently, this latter change had not been described on a <italic>FY*01</italic> background allele. Phenotype-matched units were desired for a multi-transfused Vietnamese fetus with α-thalassemia. Genotyping of the fetus using a microarray assay that interrogates three SNPs (c.1-67, c.125, and c.265) in <italic>FY</italic> yielded indeterminate results for the predicted Duffy phenotype. Genomic sequencing of <italic>FY</italic> exon 2 showed that the fetal sample had one wild-type <italic>FY*01</italic> allele and one new <italic>FY*01</italic> allele with the c.265C>T SNP, which until recently had only been found on the <italic>FY*02</italic> allele. Genotyping performed on samples from the proband’s parents indicated that the father had the same <italic>FY</italic> genotype as the fetus. Flow cytometry, which has been previously demonstrated as a useful method to study antigen strength on cells, was used to determine if this new <italic>FY*01</italic> allele was associated with reduced Fya expression on the father’s RBCs. Median fluorescence intensity of the father’s RBCs (after incubation with anti-Fya and fluorescein-labeled anti-IgG) was similar to known <italic>FY*01</italic> heterozygotes and significantly weaker than known <italic>FY*01</italic> homozygotes. In conclusion, the fetus and father both had one normal <italic>FY*01</italic> allele and one new <italic>FY*01</italic> allele carrying c.265C>T. This new <italic>FY*01</italic> allele, named <italic>FY*01W.01,</italic> is associated with weakened expression of Fya on RBCs. <italic><bold>Immunohematology</bold></italic><bold>2015;31:103–107.</bold></abstract>

Duffy antigens are important in immunohematology. The reference allele for the Duffy gene (FY) is FY*02, which encodes Fyb. An A>G single nucleotide polymorphism (SNP) at coding nucleotide (c.) 125 in exon 2 defines the FY*01 allele, which encodes the antithetical Fya. A C>T SNP at c.265 in the FY*02 allele is associated with weakening of Fyb expression on red blood cells (RBCs) (called FyX). Until recently, this latter change had not been described on a FY*01 background allele. Phenotype-matched units were desired for a multi-transfused Vietnamese fetus with α-thalassemia. Genotyping of the fetus using a microarray assay that interrogates three SNPs (c.1-67, c.125, and c.265) in FY yielded indeterminate results for the predicted Duffy phenotype. Genomic sequencing of FY exon 2 showed that the fetal sample had one wild-type FY*01 allele and one new FY*01 allele with the c.265C>T SNP, which until recently had only been found on the FY*02 allele. Genotyping performed on samples from the proband’s parents indicated that the father had the same FY genotype as the fetus. Flow cytometry, which has been previously demonstrated as a useful method to study antigen strength on cells, was used to determine if this new FY*01 allele was associated with reduced Fya expression on the father’s RBCs. Median fluorescence intensity of the father’s RBCs (after incubation with anti-Fya and fluorescein-labeled anti-IgG) was similar to known FY*01 heterozygotes and significantly weaker than known FY*01 homozygotes. In conclusion, the fetus and father both had one normal FY*01 allele and one new FY*01 allele carrying c.265C>T. This new FY*01 allele, named FY*01W.01, is associated with weakened expression of Fya on RBCs. Immunohematology2015;31:103–107.

First example of an <italic>FY*01</italic> allele associated with weakened expression of Fya on red blood cells

Immunohematology

First example of an  allele associated with weakened expression of Fy on red blood cells

Duffy antigens are important in immunohematology. The reference allele for the Duffy gene (FY) is FY*02, which encodes Fyb. An A>G single nucleotide...

First example of an FY*01 allele associated with weakened expression of Fy^a on red blood cells

Article Category: Original Report

Published Online: Oct 26, 2019

Page range: 103 - 107

DOI: https://doi.org/10.21307/immunohematology-2019-076

Keywords
Duffy, Fy, flow cytometry, genotyping, blood group antigen

© 2015 P.A. Arndt et al., published by Sciendo

First example of an FY*01 allele associated with weakened expression of Fya on red blood cells