[Molecular Mechanism Study of One Case of Novel Allele of RhD Blood Group]

To investigate the serological and genotypic characteristics of a novel allele of RhD blood group in a neonate.

Serological methods were used to identify the ABO and RhD, C, c, E, e blood types of the neonate, and to detect irregular red blood cell antibodies. Third-generation sequencing of RH gene and whole-genome sequencing were performed to analyze the variant RHD gene.

The neonate was blood type O, RhD-positive, with a phenotype of CCee. The direct antiglobulin test (DAT) and antibody screening of plasma and eluate were all negative. Third-generation sequencing results suggested the possibility of structural variation at the 3' end of the RHD gene. Whole-genome sequencing revealed that exons 3-6 of TMEM50A underwent inversion and were inserted into exon 10 of RHD, replacing the bases from position 1254+105 to 1254+792 in the coding sequence (CDS). Additionally, the following point mutations were identified in this RHD haplotype: 1136 T>C, 1254+799 G>A, 1254+804 A>G, 1254+806 T>C, 1254+832 C>T, 1254+833 A>G, and 1254+865 A>G.

Through whole-genome sequencing, this study identified a novel structural variation where an inverted segment of TMEM50A exons 3-6 was inserted into RHD exon 10.