Transfusion support for a woman with and the novel allele .

According to recent work group recommendations, individuals with the serologic weak D phenotypes should be genotyped and individuals with molecular weak D types 1, 2, 3, 4.0, or 4.1 should be treated as D+. We report an African American woman with a long-standing history of metrorrhagia, who presented for infertility evaluation. Blood grouping showed AB with a possible subgroup of A, based on mixed-field agglutination, and a serologic weak D phenotype. Results from routine red cell genotyping for the gene was incongruent with the serologic RhCE phenotype. For the surgical procedure, the patient was hence scheduled to receive group AB, D- RBC transfusions. Subsequent molecular analysis identified the and alleles for the genotype and the novel allele [] along with an allele for the genotype. Using a panel of monoclonal anti-D reagents, we showed the novel allele to represent a serologic weak D phenotype, despite occurring as a compound heterozygote, designated (). Individuals with a allele are prone to anti-D immunization, while the immunization potential of novel alleles is difficult to predict. For now, patients should be treated as D- in transfusion and pregnancy management, when they harbor a novel allele along with any allele other than , or . This study exemplifies strategies for how and when a laboratory should proceed from routine genotyping to nucleotide sequencing before any decisions on transfusion practice is made.