[Family investigation of a RHD 845A/1227A genotype individual]

This study was aimed to investigate 1 case of rare RHD845A/1227A genotype pedigree and analyse their characters. The D antigen was determined by saline method and indirect anti-globulin test (IAT), the RHD1227A, RHD845A alleles and RHD zygosity were detected by PCR-SSP assay, the RHD coding region was analysed by gene sequencing. The results showed that the serological result of RH(D) antigen was found to be negative in one sample by saline assay, but positive by IAT. The analysis of RHD gene sequence indicated that RHD genes in the 845th and 1227th location were G/A base heterozygosis, it was speculated that the individual genotype may be RHD845A/1227A. Family investigation demonstrated the proband's father was RhD negative, his mother was RhD positive, the results of PCR-SSP assay showed that his father carried the RHD1227A alleles, whose genotype was RHD1227A/RHD(-), however, his mother carried RHD845A alleles, her genotype was RHD845A/RHD(+), which proved that the proband's genotype was RHD845A/1227A, inheriting the RHD1227A and RHD845A alleles from his father and mother respectively. It is concluded that 1 case of rare RHD845A/1227A genotype is found, further study proved that this rare heterozygosis come from the hereditary of RHD845A and RHD1227A alleles, rather than the formation of individual gene mutation.