Prevalence and Diagnostic Prediction of Hemoglobin Variants in Neonates: A Study from Two Indian Hospitals Using Capillary Electrophoresis and Molecular Sequencing

Hemoglobinopathies are common genetic disorders that can affect neonates. This study aimed to evaluate the prevalence of various hemoglobin variants in newborns and identify diagnostic cutoff levels for predicting homozygosity for HbS and HbD using capillary electrophoresis and molecular sequencing. A total of 2,609 newborns were screened at Lok Nayak Hospital (LNH) and Swami Dayanand Hospital (SDH) between January 2020 and October 2021. Newborns with HbA levels ≤15% or preterm deliveries were excluded. Capillary electrophoresis was performed on dried blood spot samples. Follow-up cascade screening was done for parents and siblings of positive cases, with molecular confirmation by gene sequencing. ROC curve analysis was used to determine predictive cutoff levels for homozygosity. Of 2,163 eligible neonates, 67 (3.1%) had structural hemoglobinopathies, with the most common being HbD (1.4%), followed by HbS (0.8%). Homozygous HbD, HbS, and HbE were observed. ROC curve analysis indicated that neonatal HbD levels ≥17.6% predicted homozygosity with 100% sensitivity and 96% specificity (area under the curve = 0.984), while HbS levels ≥57.4% predicted homozygosity with 100% sensitivity and 92% specificity (area under the curve = 0.917). These structural hemoglobinopathies were present in 3.1% of neonates, with HbD being the most prevalent variant. The relative levels of various types of neonatal hemoglobins can serve as reliable predictors for homozygosity, providing an effective method for early diagnosis of hemoglobinopathies in neonates.