Molecular Genetics of Rh Blood Group Variants

The Rh blood group system is defined by the RHD and RHCE genes, which encode transmembrane proteins responsible for the D, C, c, E and e antigens on erythrocyte surfaces. Variability arises through point mutations, gene conversions, hybrid gene formation and insertions or deletions, giving rise to weak D, partial D, DEL and Rhnull phenotypes. Traditional serological methods may fail to distinguish these variants, leading to alloimmunisation risks in transfusion and pregnancy. Molecular techniques such as sequence‐specific PCR, long‐read sequencing and allele‐specific Sanger sequencing now enable accurate genotyping, revealing population-specific allele distributions—for example, high DEL frequencies in East Asia and diverse weak D clusters in Africa. Structural modelling of RhD–RhAG complexes has shed light on epitope accessibility and membrane integration, while advanced mRNA phasing approaches resolve RHCE haplotypes. Together, these advances inform tailored transfusion strategies, improve donor–recipient matching and underpin prenatal diagnostics for haemolytic disease of the foetus and newborn. Emerging genome-editing methods promise to engineer universal donor cells by ablating or modifying Rh antigens at the DNA level, signalling a new frontier in transfusion medicine.

Research from Nature Portfolio

Recent studies demonstrate the feasibility of genome editing to convert D-positive progenitors into D-negative cells. By deploying programmable nucleases targeted to the RHD locus, researchers have generated erythroid progenitor clones lacking D antigen expression. These edited cells do not agglutinate with anti-D reagents and faithfully reproduce the universal D-negative phenotype. This proof-of-concept lays the foundation for bespoke donor cell engineering, offering the prospect of eliminating alloimmunisation due to RhD mismatches and streamlining transfusion compatibility.

Molecular Genetics of Rh Blood Group Variants publication trend

The graph below shows the total number of articles in molecular genetics of rh blood group variants across all publications each year (not limited to Nature Index journals).

Technical terms

RHD gene: Gene encoding the RhD protein responsible for the D antigen on red blood cells.

Weak D phenotype: Reduced D antigen expression caused by RHD mutations leading to diminished surface density.

Partial D phenotype: Altered D antigen lacking specific epitopes, often arising from hybrid or truncated RHD variants.

DEL phenotype: Extremely low D antigen levels undetectable by standard serology but identifiable by adsorption-elution or molecular assays.

RHCE haplotype: Allelic composition of RHCE defining the C/c and E/e antigen expression profile.

Transcription activator‐like effector nucleases (TALENs): Customisable enzymes designed to introduce targeted double‐strand breaks for precise genome editing.

References

1. Genotype analysis to clarify RhD variants in discrepant samples of Chilean population. Frontiers in Immunology (2023).
2. Resolution of RHCE Haplotype Ambiguities in Transfusion Settings. International Journal of Molecular Sciences (2024).
3. Characterization of Novel RHD Allele Variants and Their Implications for Routine Blood Group Diagnostics. Biomedicines (2024).
4. Molecular dynamics of the human RhD and RhAG blood group proteins. Frontiers in Chemistry (2024).
5. Rh D blood group conversion using transcription activator-like effector nucleases. Nature Communications (2015).
6. DEL in China: the D antigen among serologic RhD-negative individuals. Journal of Translational Medicine (2021).
7. RHD allele distribution in Africans of Mali. BMC Genomic Data (2003).