A case of weak partial D type 15 diagnosed by genetic analysis

Abstract

Here, we present the case of a patient who was diagnosed as having weak partial D type 15 by genetic examination. The patient was a 44-year-old woman who was referred to our hospital for surgical treatment of uterine myoma. Because of difficulty in RhD blood typing by routine tests, precise examinations of the RhD type were performed. Measurement of anti-D agglutinin titer showed attenuation by 8-tube differences as compared with a control. An anti-D adsorption elution test revealed the presence of the D antigen in her red blood cells. Reactivity with 12 types of monoclonal anti-D antibodies showed a pattern similar to that of partial D category DFR. However, by the direct sequencing of the RhD gene of her white blood cell DNA, we found a mutation of 845G>A (Gly282Asp), leading to a final diagnosis of weak partial D type 15. No anti-D antibody was detected in her serum. Weak partial D type 15 is characterized by both a weak antigenic reaction against RhD and a partial lack of the D epitope, and the production of an allogeneic anti-D antibody has been occasionally reported. In the present case, the serological examination did not discriminate weak partial D type 15 from other types of aberrant RhD. The present case suggests that genetic examination is useful in discriminating weak partial D type 15 from other types of aberrant RhD.