Biologic and Molecular Integrative Approach for the Diagnosis of Hemoglobinopathies

Abstract

Background: Hemoglobinopathies are a major public health issue in high-prevalence regions. They result from mutations affecting globin genes, causing qualitative abnormalities or quantitative defects. Phenotypic-based diagnosis often remains presumptive. Aim: This article highlights, through a case series, the importance of integrating gene sequencing into the diagnostic workflow of hemoglobinopathies. Methods: A prospective case series of patients was conducted over a three-month period in Mohammed VI National Laboratory of Medical Analyses (Casablanca-Morocco). Blood samples collected on EDTA tubes originated from private clinical laboratories. Hemoglobin electrophoresis was performed using capillary zone electrophoresis (CZE). Molecular analysis of the β-globin gene (HBB) was carried out by Sanger sequencing. Erythrocytes indices were obtained from the referring laboratories. Results: Electrophoresis’ conclusion was coherent with findings of HBB sequencing in 3 cases (Case 1, 3 and 5). Cases 3 and 4 having thalassemia confirmed by the finding of c.118C>T heterozygous mutation; present elevated rates of HbA2. Case 4 appearing as homozygous hemoglobin S by electrophoresis was identified as compound heterozygous HbS/β⁰-thalassemia. For remaining cases, definitive conclusions have only been obtained after genetic molecular tests. Discussion: Phenotypic methods such as CZE coupled with red blood cells indices are effective when screening for hemoglobinopathies. However, they remain presumptive and have limitations in complex cases. Integrating genetic testing helps correct potential misinterpretations arising from phenotypic variability, solves complex cases and is crucial for genetic counseling as well as prevention strategies. Conclusion: Integration of molecular testing into hemoglobinopathies diagnostic algorithms can contribute to prevention in high-prevalence regions.