Carrier frequency and molecular basis of hemoglobinopathies among blood donors in eastern Morocco: Implications for blood donation and genetic diagnosis

Background

Hemoglobinopathies represent the most commonly inherited autosomal recessive blood disorders in the world. The aim of this study was to determine the carrier frequency and molecular basis of hemoglobinopathies among blood donors in eastern Morocco. This is the first study of its kind for this country.

Methods

Healthy blood donors of the BRO Biobank were included in this study. Blood samples were analyzed using an automatic blood cell analyzer for complete blood counts. Hemoglobin fractions were analyzed by capillary electrophoresis and serum ferritin was measured on a chemical and immunological analyzer. Suspected hemoglobinopathy carriers were further characterized by Sanger sequencing, Gap PCR and PCR-RFLP.

Results

The study involved 2013 blood donors, of whom 1063 were male and 950 were female (sex ratio male-to-female of 1.1). The median age of these donors was 35 years. The overall carrier frequency of hemoglobinopathies was 1.84 %, with β-thalassemia carriers being the most prevalent (0.65 %) followed by HbAC (0.55 %), α-thalassemia carriers (0.30 %), HbAS (0.1 %), HbAG-Philadelphia (0.1 %), HbAD-Ouled Rabah (0.05 %) and HbAO-Arab (0.05 %). Additionally, novel β-thalassemia variants (C6(−G) and −83(A > G)) and a structural variant (Hb D-Ouled Rabah) were discovered for the first time in Morocco.

Conclusions

This study provided the first report on carrier frequency and molecular basis of hemoglobinopathies among healthy donors in Morocco. These findings are valuable for the implementation of carrier screening and genetic diagnosis for hemoglobinopathies. Furthermore, these results justify the need to introduce pre-donation screening for hemoglobinopathy carriers in Morocco, particularly in areas with a high prevalence of carriers to enhance the overall quality of the national blood supply.