Epidemiological and molecular study of hemoglobinopathies in Mauritanian patients

Hemoglobinopathies, inherited disorders of hemoglobin (Hb), are the most common hereditary monogenic diseases of the red cell in the world. Few studies have been conducted on hemoglobinopathies in Mauritania. Therefore, the aim of this work is to establish the molecular and epidemiological basis of hemoglobinopathies in a cohort of Mauritanian patients and to determine the haplotype of the β-globin gene cluster in sickle cell subjects.

The molecular screening of Hb disorders in 40 Mauritanian patients was done by a polymerase-restriction fragment length polymorphism (RFLP) for the sickle cell disease (SCD) mutation, a PCR/sequencing method for β-thalassemia mutations, and by the multiplex polymerase chain reaction method for the α-thalassemia. The exploration of eight polymorphic sites (SNPs) within the β-globin gene cluster was conducted by PCR/RFLP method, to identify the HbS haplotypes from the sickle cell subjects.

The epidemiological study of our patients showed a high incidence in the Senegal River area (52.5%) and a high ethnic prevalence for the Heratin (47.5%) and the Pular (35%). Molecular study allowed us to identify eight different mutations in our sample analyzed. They are respectively: HbS (HBB:c.20A>T) (68.75%), Cd44 -C (HBB:c.135delC) (8.75%), -29A>G (HBB:c.-79A>G) (4.8%), -α-3.7 (g.34164_37967del3804) (3.75%), IVS-II-849A>G (HBB:c.316-2A>G) (2.25%) and Cd24T>A (HBB:c.75T>A), Hb Siirt (HBB:c.83C>G) and HbC (HBB:c.19G>A) each with (1.25%). Six different haplotypes are being explored among the SCD subjects with the Senegal haplotype as the most prevalent (66.7%), followed by Benin (10%), Arab-Indians (6.7%), Bantu (3.3%), and two atypical haplotypes.

Our findings enrich the epidemiological data in our population and could contribute to the establishment of a strategy of prevention and management through screening, genetic counseling, and prenatal diagnosis of Hemoglobinopathies in the Mauritanian population.