EFFICACY OF EXPANDED NEWBORN SCREENING IN THE EARLY DETECTION OF INBORN ERRORS OF METABOLISM: A SYSTEMATIC REVIEW

Introduction: Inborn errors of metabolism represent a heterogeneous group of genetic disorders that often present with nonspecific symptoms in the neonatal period and early infancy, making timely diagnosis particularly challenging. Early clinical manifestations may be subtle or absent, leading to diagnostic delays that can result in irreversible organ damage or death if appropriate treatment is not initiated promptly. Expanded newborn screening has emerged as a public health strategy aimed at identifying these conditions before the onset of clinical symptoms through biochemical and molecular techniques. Objective: The primary objective of this systematic review was to evaluate the efficacy of expanded newborn screening programs in the early detection of inborn errors of metabolism. Secondary objectives included assessing the impact of early detection on morbidity and mortality, evaluating diagnostic accuracy across different screening platforms, analyzing differences in outcomes based on geographic and socioeconomic contexts, identifying limitations of current screening panels, and summarizing implications for health policy and clinical practice. Methods: A systematic search was conducted in PubMed, Scopus, Web of Science, Cochrane Library, LILACS, ClinicalTrials.gov, and the International Clinical Trials Registry Platform. Eligible studies included observational studies, randomized trials, and population-based screening reports published within the last five years that evaluated expanded newborn screening for inborn errors of metabolism in human populations. Data synthesis was performed narratively, focusing on detection rates, diagnostic yield, and clinical outcomes. Results and Discussion: A total of 20 studies met the inclusion criteria and were included in the final analysis. The included studies consistently demonstrated that expanded newborn screening significantly increased the detection of inborn errors of metabolism compared with traditional screening panels. Early diagnosis through expanded screening was associated with improved clinical outcomes, reduced morbidity, and lower healthcare costs in most evaluated settings. Conclusion: Expanded newborn screening is an effective strategy for the early detection of inborn errors of metabolism and contributes to improved clinical outcomes through timely intervention. The findings support the expansion of screening panels and reinforce the need for standardized implementation and continuous evaluation within public health systems.