Molecular Characterisation of Haemoglobin Variants by High-Performance Liquid Chromatography and DNA Analysis in Antenatal Patients in Lagos State, South West Nigeria

This study provides a molecular characterisation of haemoglobin variants in antenatal patients at Lagos State University Teaching Hospital, South West Nigeria, combining high-performance liquid chromatography (HPLC) and DNA-based analysis to address the gap between phenotypic electrophoresis methods and true molecular diagnosis. Current reliance on cellulose acetate electrophoresis in Nigerian antenatal programmes frequently misclassifies variant haemoglobins, with implications for genetic counselling accuracy. A cross-sectional analytical study recruited 400 pregnant women in the first trimester. HPLC was performed on all samples using the BioRad VARIANT II system, and samples with ambiguous or variant elution profiles were subjected to gap-PCR and reverse dot-blot hybridisation for molecular genotyping. Abnormal haemoglobin variants were identified in 34.5 percent of participants on HPLC. HbAS constituted 23.3 percent, HbAC 4.8 percent, HbSC 2.5 percent, HbSS 1.8 percent, and HbSD, HbSE, and HbJ were each identified in less than 1 percent. Molecular analysis reclassified 8.2 percent of samples previously reported as HbAS by electrophoresis as different variant combinations. The carrier detection rate improvement with HPLC-DNA combined approach versus electrophoresis alone was 23 percent. These findings directly impact genetic counselling accuracy and recurrence risk calculation for affected offspring. The study recommends national adoption of HPLC as the standard antenatal haemoglobin screening method with molecular confirmation for all variant-carrying women. Keywords: haemoglobin variants, HPLC, molecular characterisation, antenatal screening, Lagos.