[Determination of human RHD gene rhesus box and its significance]

The aim was to determine RHD zygosity, further to investigate genetic structure of RHD gene, and to predict hemolytic disease of newborn (HDN). The upstream box, downstream box, and hybrid box of RHD gene were determined by PCR-SSP with 4 primers under the same conditions. The results showed that only hybrid box could be determined in RHD(-)/RHD(-) homozygosity. All the upstream box, downstream box, and hybrid box could be determined in RHD(+)/RHD(-) heterozygosity, while upstream box and downstream box except hybrid box could be determined in RHD(+)/RHD(+) homozygosity. Out of 50 cases of RhD(+), 5 cases (10%) were RHD(+)/RHD(-) heterozygosity, and the others (90%) were RHD(+)/RHD(+) homozygosity. 54 cases (55.1%), 36 cases (36.7%) and 8 cases (8.2%) were RHD(-)/RHD(-) homozygosity, RHD(+)/RHD(-) heterozygosity, and RHD(+)/RHD(+) homozygosity respectively in 98 unrelated cases of RhD(-) Chinese Hans. 2 cases of weak D were proved to be RHD(+)/RHD(-) heterozygosity. Out of 16 D(el) types, the upstream box, downstream box, and hybrid box could be determined in 10 cases (37.5%) and the upstream box and downstream box except hybrid box could be determined in 6 cases. Results detecting of RHD 10 exons in above samples proved the correctness of the method. It is concluded that the method is suitable for clinical application with its simplicity and veracity. There are many noneffective RHD genes (44.9%) in Chinese Hans with RhD(-) phenotype.