Haemoglobinopathies: Integrated Biochemical and Molecular Diagnosis in 5243 Patients

Background: Haemoglobinopathies are among the most common monogenic disorders worldwide. Early identification of asymptomatic carriers through reliable screening and molecular diagnostics is crucial for prevention programmes, especially in high-prevalence regions such as Southern Italy. Methods: A total of 5243 individuals were analysed between 2013 and 2024 using both biochemical and genetic parameters. First-level screening included full blood count, iron status, and high-performance liquid chromatography (HPLC) for haemoglobin variant quantification. Molecular analyses were performed using next-generation sequencing (NGS) for the HBA1, HBA2, and HBB genes. Results: We identified 267 individuals (11.2%) as carriers of α-thalassaemia and 473 individuals (16.7%) as carriers of β-thalassaemia. Among them, 5 were compound heterozygotes and 3 homozygous for the α-3.7 deletion. A rare case of HbG Philadelphia in association with a triplicated α-gene was also observed. The most common β-globin mutations included c.118C>T (β039, 44%), IVS-I-110 (17.7%), IVS-I-6 (12.7%), and IVS-I-1 (12.3%). Among α-globin mutations, the most prevalent were -α3.7 (48%), α2 IVS1 -5nt (15.4%), -20.5 Kb (14.2%), and triplicated α (11%). In total, 18.7% of individuals were found to carry either α- or β-thalassaemia traits. Conclusion: Our findings highlight the limitations of traditional diagnostic methods—such as the osmotic fragility test—and the importance of integrating haematological, biochemical, and molecular data to accurately identify thalassaemia carriers. The variability of genotype–phenotype correlations, especially in the context of immigration and genetic diversity, underscores the need for comprehensive molecular analysis. We propose a three-step diagnostic algorithm combining first-level screening, iron status assessment, and NGS-based sequencing for inconclusive cases.