DNA analysis for the Dombrock polymorphism

BACKGROUND: RBC typing for Do(a) and Do(b) is notoriously difficult, and in accurate typing can predispose patients to hemolytic transfusion reactions. The DO1/DO2 polymorphism is associated with three nucleotide changes: 378 C >T, 624 T >C and 793 A >G. While the 378 C >T- and 624 T >C-containing co dons are silent mutations. the 793 A >G polymorphism in codon 265 encodes a sparagine for Do, and aspartic acid for Do(b). STUDY DESIGN AND METHODS: Described here are two PCR-RFLP assays, one using the Mnl I site associated with 624C (DO2) and the other altering two nucle otides within the sense primer, which allows recognition of 793G by the Eam 1105 I. RESULTS: The assays have been performed on over 100 samples for which the R BC typing of one or both antigens was known. Eight samples had been histori cally mistyped by hemagglutination. CONCLUSION: This RFLP assay provides a practical method for typing donor bl ood for Dombrock alleles.