The Duffy blood group system in the Tunisian population.

Background: Tunisia was described to as genetically heterogenous. Besides the 1% native Berber, the genetically influence of the Europeans seems much larger than that of sub-Saharan populations. Due to their ethnic variability, blood group variants have the potential to support population analyses. The aim of this study was to estimate the Duffy blood group system in this mixed population with enhanced characterization of samples with aberrant expression.

Materials And Methods: Standard serological testing for the Duffy antigen was done for 105 Tunisian blood donors. Samples with altered Fy expression underwent DNA sequencing of the DARC, RHD and RHCE genes.

Results: The Fy(a-b+) was the most common phenotype identified in the Tunisian population (38.1%). Five samples with Fy(a-b-) phenotype were determined as FY*02N.01/FY*02N.01 by a homozygous occurrence of the FY*B-67C>T alteration. Another three individuals exhibited a Fy(b+(w))Fy(x) expression, confirmed by a FY*A/FY*02M.01 (n = 1) and a FY*02M.01/FY*02M.01 (n = 2) genotype. RHD and RHCE sequencing (n= 8) revealed altered alleles observed in black populations in 5 samples. One individual with FY*02M.01/FY*02M.01 have the silent 165C>T nucleotide substitution each in the RHD and RHCE gene.

Discussion: The composition of blood group variants determined in this study confirms the genetically proximity of Tunisia to Europe. The small sub-Saharan genetic influence was approved by a limited number of variant samples associated with the black population.