Haemoglobinopathies in Newborn Screening: Epidemiological Findings and Exploratory Analysis of HbA0 Distribution in a Population-Based Neonatal Cohort from Northern Italy

Haemoglobinopathies are an increasing health concern in Europe due to changing population demographics. In Italy, however, newborn screening (NBS) for haemoglobinopathies is not yet included in the national mandatory screening panel. The primary aim of this study was to estimate the prevalence of haemoglobinopathies in a population-based neonatal cohort from the Piedmont region; a secondary exploratory objective was to characterise neonatal HbA0 distribution and its association with molecular findings in selected samples. We conducted a retrospective, multicentre study of 2002 anonymised dried blood spot samples collected from term newborns 48–72 h after birth. Haemoglobin fractions were analysed by high-performance liquid chromatography (HPLC). HbA0 distribution was characterised in newborns without structural haemoglobin variants using descriptive statistics. Molecular analysis was performed in an intentionally selected subset of samples with HbA0 < 12%. HPLC identified 29 structural haemoglobin variants (22 HbS and 7 other variants), corresponding to a prevalence of 1.4%. After exclusion of these cases, HbA0 distribution was analysed in 1973 newborns. Mean HbA0 was 16.1% (SD 5.3), median HbA0 was 15.5% (Q1–Q3: 12.3–19.1), and the distribution showed moderate positive skewness. Overall, 448/1973 newborns (22.7%) had HbA0 < 12%. Among 12 selected newborns with HbA0 < 12% who underwent molecular testing, detectable β-globin gene mutations were identified in five. DNA extracted from stored dried blood spots was suitable for molecular analysis. Structural haemoglobin variants were identified in a non-negligible proportion of newborns in this Northern Italian cohort. HPLC provided effective first-line identification of the variants observed, whereas neonatal HbA0 showed substantial variability and an asymmetric distribution, supporting cautious interpretation of fixed absolute thresholds for suspected β-thalassaemia carrier status. Larger, systematically genotyped cohorts are required to assess the diagnostic performance of candidate HbA0 thresholds.