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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
Author(s) -
Lopez G. H.,
Morrison J.,
Condon J. A.,
Wilson B.,
Martin J. R.,
Liew Y.W.,
Flower R. L.,
Hyland C. A.
Publication year - 2015
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1111/vox.12273
Subject(s) - genotyping , biology , genotype , genetics , high resolution melt , allele , single nucleotide polymorphism , snp genotyping , phenotype , snp , typing , null allele , microbiology and biotechnology , gene
Background and objectives Duffy blood group phenotypes can be predicted by genotyping for single nucleotide polymorphisms ( SNP s) 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. Materials and 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. Conclusion 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.