[Application of Third-Generation Sequencing Technology in RHD Genotyping of a Chinese Pedigree with Weak D Phenotype]

To investigate the molecular mechanism of weak D phenotype in a Chinese family.

Routine Rh typing tests were performed first, and RHD exons 1-10 of the proband and his family members were sequenced by first-generation sequencing. RHD zygosity was also determined. Third-generation sequencing was used to analyze the haplotypes of the RHD gene.

The proband showed a weak D serological phenotype. First-generation sequencing revealed a c.787G>A point mutation in exon 5. The family pedigree investigation showed that the proband and his younger sister had the same serological phenotype and molecular mechanism. His father carried this gene mutation, while his mother and younger brother were normal. Hybrid box was not detected, suggesting that all the family members did not have a haplotype with a complete deletion of the RHD gene. The results of third-generation sequencing showed that the proband and his sister inherited the weak D allele from their father and the non-functional allele RHD -CE(3-9)-D from their mother, respectively.

Third-generation sequencing technology enables haplotype analysis of the RHD gene and can detect complex genotypes such as genetic exchanges between RHD and RHCE combined with other mutations.