A clinically applicable method for determining the three major alleles at the Duffy (FY) blood group locus using polymerase chain reaction with allele-specific primers

BACKGROUND: The clinically significant antigens of the Duffy (Fy [FY]) blood group system are expressed on the red cell form of the PI glycoprotein, a promiscuous chemokine receptor and also a receptor for malarial parasites. After the cloning of cDNA coding for FY glycoprotein, the molecular basis of the three major alleles (Fy(a)/Fy(b)/Fy) has been established. Because of the mistyping of the silent Fy allele as Fy(b), the error rate of current genotyping methods is high in black populations. STUDY DESIGN AND METHODS: Two hundred blood donors (European whites and African Blacks) and some amniotic DNA samples were investigated by a new allele-specific primer polymerase chain reaction technique. Sense primers corresponding to normal and GATA-1-mutated FY gene promoter region sequences were combined with antisense primers discriminating the Fy(a)/Fy(b) polymorphism. RESULTS: Complete correlation between FY phenotypes and genotypes was obtained in all samples studied, although, in two whites and one black, serology showed weak Fy(b) expression while polymerase chain reaction indicated a Fy(b) allele. Gene frequencies were calculated. CONCLUSION: This simple and rapid polymerase chain reaction method was shown to detect the three common alleles at the FY locus in two representative ethnic populations. Its future use as an independent technique in red cell FY investigations and for fetal genotyping in hemolytic disease of the newborn is predicted.