[Molecular background of weak D type 15 as the predominant weak D type found in Chinese population]

This study was aimed to investigate the molecular genetic basis and serological phenotype of Rh weak D type 15 individuals. Samples were identified by serological tests and genotyped by sequence specific primer-PCR (SSP-PCR), and were sequenced to detect the changes of all ten RHD exons. The number of gene RHD was detected through SSP-PCR. The results showed that in tested individuals of weak D type confirmed by the IAT, 18 cases (56% in weak D) were weak D type 15. Rh factors found in 2 weak D type 15 individuals (11%) were C+c+E+e; Rh factors found in 2 weak D type 15 individuals (11%) were C+c+E-e+; others (78%) were c-c+E+e+. The results by serological tests were consistent with the results genotyped by PCR-SSP method. In all 18 samples, the sequencing result revealed a gene mutation 845G > A at the exon 6 of the RHD and the point mutation changed amino acid G282D of the RhD polypeptide. The zygosity test demonstrated that 2 out of 18 weak D type 15 individuals were RHD(+)/RHD(+) homozygous (two DCe/DcE), 16 cases were RHD(+)/RHD(-) heterozygous (two DCe/dce and fourteen DcE/dce). It is concluded that Weak D type 15 is predominant in weak D individuals of Chinese Han Nationality, and most of them are heterozygous with various RH haplotypes.