Interstitial lung diseases are a heterogeneous group of disorders that are poorly understood at a molecular level.1,2 The cause is often unknown, and the histologic diagnoses used in adults may represent different disease processes in children.3–5 For example, cases of desquamative interstitial pneumonitis reported in infants are often more severe and refractory to treatment than those reported in adults.6,7 Many of these cases probably represent chronic pneumonitis of infancy.8,9 The lungs in patients with chronic pneumonitis of infancy are characterized by interstitial thickening with mesenchymal cells, rather than by an inflammatory infiltrate, and an alveolar infiltrate . . .

A Mutation in the Surfactant Protein C Gene Associated with Familial Interstitial Lung Disease