Distribution of Hemoglobin Variants: A Retrospective Study Based on Hemoglobin Electrophoresis Results From a University Hospital in Madagascar.

INTRODUCTION

Inherited hemoglobin disorders, including sickle cell disease and thalassemias, are a growing public health burden, particularly in low-resource countries. Data from Madagascar remain limited. This study describes the distribution of hemoglobin variants and evaluates methodological considerations using agarose gel electrophoresis in patients referred for laboratory analysis.

METHODS

A retrospective study was conducted on 553 patients (2014-2019) referred for hemoglobin analysis. Hemoglobin variants were identified using agarose gel electrophoresis (Hydrasys system, Sebia). Demographic data and temporal trends were analyzed.

RESULTS

Normal hemoglobin profiles were observed in 133 patients (24.1%). HbAS was the most frequent variant (247; 44.7%), followed by HbSS (105; 19.0%). Isolated alpha-thalassemia and beta-thalassemia were rare, 1 (0.2%) and 7 (1.3%). Combined hemoglobinopathies were observed, predominantly HbAS with alpha-thalassemia (29; 5.2%) and HbAS with beta-thalassemia (17; 3.1%). Agarose gel electrophoresis provided accessible detection of common variants but may underestimate or misclassify rare or complex variants due to co-migration and limited quantification.

CONCLUSION

Sickle cell-related hemoglobinopathies are highly prevalent in Madagascar, with significant genetic heterogeneity including combined forms. While agarose gel electrophoresis is practical in resource-limited settings, complementary techniques such as high-performance liquid chromatography or molecular analysis are recommended for accurate diagnosis. These findings support the need for strengthened screening programs and improved diagnostic capacity to better manage hemoglobinopathies in Madagascar.