A novel c.790C>T mutation in RHAG gene encoding the Rhnull phenotype in Japanese

Abstract

Background and ObjectivesMolecular analyses of Rhnull individuals have revealed that abnormalities occur only at the RH or RHAG gene. Rhnull phenotype arises from two distinct genetic mechanisms, the amorph and the regulator type. Here, we genetically analysed a Japanese Rhnull family and identified a novel RHAG mutation.Materials and MethodsRBC samples from two family members were phenotyped using the standard serological techniques and BLOODchip Reference for the predicted phenotype. Scanning electron micrographs of red blood cells (RBCs) were generated. All 10 RHAG exons were subjected to DNA sequencing.ResultsRBCs in 2 Rhnull samples did not contain Rh or RhAG antigens. The screening tests for irregular RBC antibodies identified anti‐Rh29 in 2 samples and anti‐C+e in the older sister of the proband. A molecular base analysis revealed a novel c.790C>T (p.Arg263X) mutation in exon 5 of RHAG gene.ConclusionThe samples with the novel c.790C>T (p.Arg263X) mutation in exon 5 of the RHAG gene were identified as regulator type.