title: Duffy blood group phenotype-genotype correlations using high-resolution melting analysis PCR and microarray reveal complex cases including a new null FY*A allele: the role for sequencing in genotyping algorithms.
abstract: OBJECTIVE
  Duffy blood group phenotypes can be predicted by genotyping for single nucleotide polymorphisms (SNPs) responsible for the Fy(a) /Fy(b) polymorphism, for weak Fy(b) antigen, and for the red cell null Fy(a-b-) phenotype. This study correlates Duffy phenotype predictions with serotyping to assess the most reliable procedure for typing.
  
  
  METHODS
  Samples, n = 155 (135 donors and 20 patients), were genotyped by high-resolution melt PCR and by microarray. Samples were in three serology groups: 1) Duffy patterns expected n = 79, 2) weak and equivocal Fy(b) patterns n = 29 and 3) Fy(a-b-) n = 47 (one with anti-Fy3 antibody).
  
  
  RESULTS
  Discrepancies were observed for five samples. For two, SNP genotyping predicted weak Fy(b) expression discrepant with Fy(b-) (Group 1 and 3). For three, SNP genotyping predicted Fy(a) , discrepant with Fy(a-b-) (Group 3). DNA sequencing identified silencing mutations in these FY*A alleles. One was a novel FY*A 719delG. One, the sample with the anti-Fy3, was homozygous for a 14-bp deletion (FY*01N.02); a true null.
  
  
  CONCLUSIONS
  Both the high-resolution melting analysis and SNP microarray assays were concordant and showed genotyping, as well as phenotyping, is essential to ensure 100% accuracy for Duffy blood group assignments. Sequencing is important to resolve phenotype/genotype conflicts which here identified alleles, one novel, that carry silencing mutations. The risk of alloimmunisation may be dependent on this zygosity status.
authors.affiliation: Research and Development, Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia.
authors.forename: G H
authors.initials: GH
authors.lastname: Lopez
authors.affiliation: Red Cell Reference Laboratory, Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Morrison
authors.affiliation: Red Cell Reference Laboratory, Australian Red Cross Blood Service, West Melbourne, VIC, Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Condon
authors.affiliation: Red Cell Reference Laboratory, Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Wilson
authors.affiliation: Red Cell Reference Laboratory, Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia.
authors.forename: J R
authors.initials: JR
authors.lastname: Martin
authors.affiliation: Red Cell Reference Laboratory, Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia.
authors.forename: Y-W
authors.initials: YW
authors.lastname: Liew
authors.affiliation: Research and Development, Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia.
authors.forename: R L
authors.initials: RL
authors.lastname: Flower
authors.affiliation: Research and Development, Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia.
authors.forename: C A
authors.initials: CA
authors.lastname: Hyland
mesh_terms: D000465:Algorithms; D000483:Alleles; D001483:Base Sequence; D004375:Duffy Blood-Group System / Q000235:genetics*; D056726:Genetic Association Studies; D006801:Humans; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D044367:Phase Transition; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011956:Receptors, Cell Surface / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: C473745:ACKR1 protein, human; D004375:Duffy Blood-Group System; D011956:Receptors, Cell Surface
keywords: Duffy blood group genotyping; Duffy null FY*01N.07; RBC antigens and antibodies; high-resolution melting analysis; serological testing