ABSTRACT
<p><b>OBJECTIVE</b>To analysis the genetic mode of Rh DEL phenotype and RHD 1227A allele in Zhejiang Han population through family investigations.</p><p><b>METHODS</b>Rh DEL phenotypes were identified by a serologic adsorption-elution method. Two polymerase chain reaction-sequence specific prime (PCR-SSP) methods which detectED RHD 1227A allele and Rhesus hybrid box, respectively, and a nucleotide sequencing method focused on the exon 9 of RHD 1227A allele were employed to determine the zygosity of RHD allele.</p><p><b>RESULTS</b>All five probands with Rh DEL phenotype harbored a RHD 1227A allele and had a RHD allele deletion, and they were RHD 1227A/RHd heterozygote. One of the parent members was found to contain a RHD 1227A allele and a normal RHD allele in pedigree 1, 2 and 3, respectively. Thus, they were RHD 1227A/RHD heterozygotes and presented normal D positive phenotype. The son of proband No 1. inherited the RHD 1227A allele and presented a normal D positive phenotype due to a RHD 1227A/RHD heterozygote; The offsprings of proband No. 2, No. 4, and No. 5 did not inherit RHD 1227A allele and presented a normal D positive phenotype.</p><p><b>CONCLUSION</b>RHD 1227A allele is an important genetic marker of Rh DEL phenotype; RHD 1227A is recessive to normal RHD allele and dominant to RHd allele; RHD 1227A allele is an ancestral, but not a spontaneously mutated allele.</p>