Rapid genotyping of the major alleles at the Duffy (FY) blood group locus using real-time fluorescence polymerase chain reaction

The Duffy blood group system has clinical importance due to involvement in transfusion reactions and hemolytic disease of the newborn. Recently, the molecular basis of the two alleles, FY*A and FY*B (125G>A), and the mutation situated in the promoter region of the FY gene (–33T>C), have been elucidated. In order to develop an accurate, easy, and rapid genotyping method, we describe a procedure using the LightCycler^®. Samples from 53 Caucasian Portuguese blood donors and 7 black, healthy, European individuals were phenotyped with commercial antisera. DNA was extracted from blood samples and the relevant sequences were amplified with the same cycling conditions, using real-time polymerase chain reaction. The melting point of the FY*A allele was 63°C and of the FY*B allele, 55°C. The allele without mutation at the promoter region had a melting point at 64°C and the FY*B silent allele at 58°C. The results in Caucasian individuals were similar to those found in European and American populations. When FY genotyping techniques are necessary, the methodology described is preferable to conventional methods as it is reliable, high speed, and uses small volumes, providing a highly competitive technology for use by a routine laboratory. Immunohematology 2001;17:42–44.