Background: Childhood interstitial lung diseases (chILD) include a large spectrum of diseases. Besides the genetically defined surfactant dysfunction disorders, most present pathologically involve the alveolar surfactant region, possibly affecting the surfactant proteins. The aim of this study was to investigate the prevalence of surfactant protein disorders (SPD) in patients with chILD and to evaluate the clinical spectrum of these patients.

Methods: This retrospective cohort study was conducted at a tertiary referral pediatric pulmonology center between January 2010 and December 2020. Children who were evaluated for interstitial lung diseases younger than two years were included in the study.

Results: Among 135 children with ILD, 20 patients were evaluated in detail for surfactant dysfunction disorder etiology, and eight patients were further diagnosed with ILD related to SPD. The prevalence of SPD in our patients with chILD was 5.9%. Five (62.5%) of these patients were male. The most common initial symptom was tachypnea. The most common physical examination sign was crackling in both lungs. One patient had protein C deficiency, two had adenosine triphosphate binding cassette 3 (ABCA3) mutation, 4 had polymorphism in the surfactant protein C gene, and one had polymorphism in the surfactant protein B gene. One of those patients died because of respiratory insufficiency. 

Conclusion: The surfactant proteins gene mutations and even polymorphisms are associated with pediatric interstitial lung disease.