OBJECTIVETo report a case of pulmonary surfactant protein (SP) gene mutation associated with pediatric interstitial lung disease, and study the clinical diagnosis process and review of related literature, to understand the relationship between interstitial lung disease and SP gene mutation in infants and children.

METHODThe clinical, radiological, histological, and genetic testing information of a case of SP gene mutation related pediatric interstitial lung disease were analyzed and related literature was reviewed.

RESULTA 2-year-old girl without a history of serious illness was hospitalized because of the shortness of breath, cough, excessive sputum, and the progressive dyspnea. Physical examination on admission revealed tachypnea, slight cyanosis, and the retraction signs were positive, respiratory rate of 60 times/minute, fine crackles could be heard through the lower lobe of both lungs; heart rate was 132 beats/minute. No other abnormalities were noted, no clubbing was found. Laboratory test results: pathologic examination was negative, multiple blood gas analysis suggested hypoxemia. Chest CT showed ground-glass like opacity, diffused patchy infiltration. Bronchoalveolar lavage fluid had a large number of neutrophils, and a few tissue cells. Eosinophil staining: negative. Fluconazole and methylprednisolone were given after admission, pulmonary symptoms and signs did not improve, reexamination showed no change in chest CT. Then lung biopsy was carried out through thoracoscopy. Histopathology suggested chronic interstitial pneumonia with fibrosis. The heterozygous mutation of R219W in the SFPTA1 and the S186N in SFTPC were identified by SP-related gene sequencing. The review of related literature showed that polymorphisms at the 219th amino acid in SP-A1 allele were found in adults with idiopathic pulmonary fibrosis (IPF), but there is no related literature in pediatric cases. The patient in this report had a mutation at the SP-A1 allele consistent with related literature. Data of 17 young children with mutation in SP-C gene showed that all the 17 cases had dyspnea and tachypnea, chest CT revealed diffuse opacities in lungs, the pathology of lungs was NSIP and CPI. There were 17 kinds of mutation and the common mutation was I73T. The mutation of S186N in SFTPC in our case has never been shown in previously published literature.

CONCLUSIONA case of interstitial lung disease with S186N gene mutation in SFTPC was preliminarily diagnosed in an infant. The SP-C gene mutations and polymorphisms are associated with pediatric interstitial lung disease.