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

β-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 β-globin chain synthesis. The severity of the disease depends on the nature of the variants affecting the β-globin gene (HBB), and each ethnic group has its own mutation spectrum. Hereby, we present, for the first time, the molecular profile of β-thalassemia in the Eastern region of Morocco.

This study concerns 39 cases from 33 families who were enrolled in the BRO Biobank. Nineteen were diagnosed with β-thalassemia major and 20 with β-thalassemia minor. To detect mutations of the β-globin gene, we have used RFLP-PCR and Sanger sequencing.

Nine known β-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 β-thalassemia is very different from that found in previous studies in Morocco or in other North African countries.

This study is the first contribution to the description of the molecular profile of β-thalassemia in the Eastern region of Morocco. It shows the high molecular heterogeneity of β-thalassemia in our country. Therefore, these results can be valuable for the implementation of carrier screening, genetic counseling, and prenatal diagnosis programs.