[Molecular Mechanism of a Rhesus D Variant Individual with 845A/1227A].

Objective: To explore the genetic mutation mechanism of a rare Rhesus D variant individual.

Methods: Regular serological assay was used for determination of Rh type for the sample. Indirect anti-human globulin test (IAT) was used to confirm the RhD antigen and screen the antibodies. D-screen reagent was used to analyze the RhD epitopes of the sample. genotype and zygosity testing of the sample were detected by palymerase chain reaction with sequence-specific primers (PCR-SSP). The full length coding region of gene was sequenced. mRNA was detected using reverse transcription polymerase chain reaction (RT-PCR). The PCR products were cloned and sequenced.

Results: The RhD blood group of the sample was determined as weak D, and the Rh phenotype was CcDEe. The antibody screening was negative. The sample tested with all monoclonal anti-Ds in D-screen showed the D epitope profiles as partial D types. The analysis of gene sequence indicated that the individual with c.845G/A and c.1227G/A base heterozygosis. Three kinds of alternative splicing isoforms were obtained by TA cloning and sequencing.

Conclusion: The object has c.845G/A and c.1227G/A mutation. This heterozygous mutation is responsible for the low expression of RhD antigen on the red blood cells of the sample.