OBJECTIVETo explore the molecular basis for an individual with a rare weak D phenotype.

METHODSSerological methods were used to characterize the RhD blood group phenotype. The exons of RHD gene were amplified with PCR and sequenced. The presence of Rhesus box was tested by PCR to determine the homozygosity of RHD gene.

RESULTSThe RhD blood group of the proband was detected as weak D. The 10 exons of the RHD gene and Rhesus box could be amplified by PCR, and the genotype of RHD alleles was determined as RHD+/RHD-. The exons of the RHD gene were sequenced, and a 365C>T mutation in exon 3 was detected. Therefore, the RhD blood group of the proband was confirmed as weak D type 54 by both serological methods and DNA sequencing.

CONCLUSIONA weak D type 54 has been detected. A 365C>T mutation in RHD gene is responsible for the low expression of D antigen.