RHD alleles in the Tunisian population

Area of Science:

• Immunogenetics
• Molecular Biology
• Population Genetics

Background:

• Limited data existed on Rhesus rhesus (RH) D (RHD) alleles in the Tunisian population.
• The RHD/RHCE deoxyribonucleic acid (DNA) sequence exchange mechanism and weak D alleles are significant in transfusion medicine.

Purpose of the Study:

• To conduct a comprehensive survey of RHD alleles in Tunisia.
• To utilize a multiplex RHD typing assay for simultaneous detection of partial D and weak D alleles.

Main Methods:

• Designed six RHD-specific primer sets to amplify RHD exons 3, 4, 5, 6, 7, and 9.
• Performed RHD genotyping on 2000 blood donors (1777 D+ and 223 D-) using a multiplex PCR assay.
• Conducted further molecular investigations to characterize identified RHD variants.

Main Results:

• Weak D type 4 variants were identified in 10 of 1777 D+ samples (absence of RHD exons 4 and 5).
• No hybrid RHD alleles were detected.
• RHD exon amplification was observed in 5 of 223 D- samples, including RHD exon 9 expression and absence of RHD exons 4 and 5.

Conclusions:

• Weak D type 4 is the predominant RHD variant allele in the Tunisian population.
• No partial D variants were identified.
• RHD gene deletion is the most frequent cause of the D- phenotype in Tunisia.