Several authors have highlighted the interest of studying hemoglobin haplotypes for individuals with hemoglobin disorders as a modulation of the clinical profile of the disease [7,8,9,10,11,12,13,14]. In Côte d'Ivoire, there is not available data on hemoglobin haplotypes. This study updates data on hemoglobin haplotypes in Côte d'Ivoire amongst individuals living in Abidjan and experimenting mild malaria. During this work, women represented the highest proportion of people attending dispensaries. This is frequently observed as men use to practice self-treatment so they rarely visit dispensaries. Our study indicated a prevalence of 13% of sickle cell trait (3% of SCD) in the population analyzed. Previous studies conducted by Tossea et al. [18] in the same area reported a similar prevalence. This concordance could be due to the design of the two (02) studies. Indeed, these studies were carried out in individuals with middle malaria in Abidjan.
The Benin haplotype was the most prevalent followed by the Bantu one, which can be attributable respectively to ethnic origin of the population in Abidjan, and the high level of migration from central Africa to Ivory Coast. Arab-Indian haplotype was not observed despite migration of populations across the Sahel (Peul and Toucouleur ethnics). A small prevalence of Senegal and Cameroon haplotypes was observed. These different prevalence are in accordance with the geographical distribution of the different populations [5, 6].
Similar to the studies of several authors who reported 5–10% of atypical haplotypes [9, 19,20,21], we found 10% of atypical haplotypes in the population of Abidjan, mostly associated with the Benin haplotype. Due to the fact that the Benin haplotype is associated with a more severe form of expression of SCD and considering the high prevalence of atypical haplotypes, the relationship between these haplotypes and the clinical pattern of sickle cell disease should be investigate further.
Overall a high proportion of heterozygous genotype (61%) was found in Abidjan. That differs from the studies conducted by Doupa et al. (32%) [17]. This difference could be due to their selection of patients harboring SCD and to the limitation of that study to only a single restriction site.
The emergence of these atypics haplotypes and the high proportion of heterozygous haplotypes could support a high level of mixed populations. Indeed, Abidjan is one of the major city in West Africa, with a cosmopolite population. In addition, the important mixing of populations would be a factor in the development of genetic phenomena such as chromosomal recombination’s between haplotype.
Different atypical haplotypes observed show strong similarities with the Benin and Bantu haplotypes. Several others authors [19, 22, 23] obtained similar results relative to atypical haplotypes. The high proportion of atypical haplotype and its similarity with the Benin haplotype could be explained by selection pressure. Indeed, the association of the atypical haplotypes with the more severe Benin haplotype may lead to a more moderate expressive expression of sickle cell disease. More insight studies need to be conducted to explore such associations and their clinic expressions.