Molecular characterization of the Fy(a−b−) phenotype in a Polish family

The Fy(a−b−) phenotype, very rare in Caucasians and defined by the homozygous FY*B-33 allele, is associated with the −33T > C mutation in the promoter region of the FY gene. The allele FY*X is correlated with weak expression of Fyb antigen due to 265C > T and 298G > A mutations in FY*B allele. The purpose of this study was molecular characterization of Fy blood group antigens in Fy(a−b−) members of a Polish family. High-resolution melting analysis was performed to detect single nucleotide polymorphisms in amplified fragments of the FY gene. The Fy(a−b−) phenotype in three siblings of the Polish family was caused by the FY*X/FY*B-33 genotype.