Rare ABCA3 Gene Mutation: Clinical Presentation and Treatment in Infancy and Childhood

<bold>Introduction:</bold> Interstitial lung disease (ILD) encompasses a group of lung diseases affecting lung interstitium and distal airways. Genetic disorders, particularly those causing dysfunction in alveolar surfactant proteins, are uncommon but significant causes of ILD in pediatric patients. Mutations in the ABCA3 gene can result in various clinical presentations within this disease spectrum. This study aims to discuss the clinical, genetic, and treatment outcomes of two siblings presenting with dyspnea and hypoxemia. Case: A four-year-old girl and her one-year-old brother presented with symptoms including exertional dyspnea, hypoxemia, cough, low oxygen saturation, and growth retardation. Areas of consolidation, ground-glass opacities, fibrotic changes were observed on lung tomography. Both were found to have the c.128G>A mutation in the ABCA3 gene. Treatment included oxygen and mechanical respiratory support, along with hydroxychloroquine and methylprednisolone therapy. From the second month of treatment onwards, signs of hypoxemia improved, and their exercise capacities increased. By the second year of follow-up, our female patient no longer required oxygen supplementation and was able to maintain a normal life with only low-level oxygen therapy at night. <bold>Conclusion:</bold> Suspected surfactant protein dysfunction should be considered in cases of unexplained respiratory distress, particularly in larger children. ABCA3-associated ILD progresses into childhood and requires tailored treatments for improved prognosis. Developing treatments will be an important step for improving the prognosis of this serious and often life-limiting disorder. Keywords: ILD, ABCA3, hypoxemia, hydroxychloroquine