Molecular heterogeneity of beta-thalassemia variants in the Eastern region of Morocco

Background: beta-thalassemia syndromes are the most common hereditary blood disorders in the world and are recognized as a major health problem in Morocco. They are characterized by the reduction or the absence of beta-globin chain synthesis. The severity of the disease depends on the nature of the variants affecting the beta-globin gene (HBB), and each ethnic group has its own mutation spectrum. Hereby, we present, for the first time, the molecular profile of beta-thalassemia in the Eastern region of Morocco. Methods: This study concerns 39 cases from 33 families who were enrolled in the BRO Biobank. Nineteen were diagnosed with beta-thalassemia major and 20 with beta-thalassemia minor. To detect mutations of the beta-globin gene, we have used RFLP-PCR and Sanger sequencing. Results: Nine known beta-thalassemia variants have been identified. Among these, we reported, for the first time in the Moroccan population, the Czechoslovakian variant C38/39(-C) at homozygous state. The C39(C > T) was the most frequent variant (72.54%), followed by FSC5(-CT) (5.88%), FSC6(-A), IVS-1-110(G > A), -29(A > G), C38/39(-C) (3.92% each), and finally by IVS-I-1(G > A), IVS-II-1(G > A), and -56(G > C) (1.96%). Of particular interest this mutational spectrum of beta-thalassemia is very different from that found in previous studies in Morocco or in other North African countries. Conclusion: This study is the first contribution to the description of the molecular profile of beta-thalassemia in the Eastern region of Morocco. It shows the high molecular heterogeneity of beta-thalassemia in our country. Therefore, these results can be valuable for the implementation of carrier screening, genetic counseling, and prenatal diagnosis programs.