Children’s Interstitial and Diffuse Lung Disease (chILD) is not a single disease. Instead, chILD is a heterogeneous group of rare lung diseases that affect infants and children. Some of these diagnoses are unique to children, but many are seen throughout the lifespan and can be expressed in both children and adults. Adults can also suffer from ILD. Some diagnoses are only seen in adults, and most physicians consider adult ILD a totally different disease than chILD. The most common and severe form of adult ILD is usually interstitial pneumonia/idiopathic pulmonary fibrosis, which has not been found in infants and young children. The term “idiopathic pulmonary fibrosis” means scarring of the lungs for unknown reasons and can occur in children and adults, however, the adult version may not be the same disease process in infants and young children. Recently more families are being discovered that have multiple generations with pulmonary fibrosis that begins in different age categories. This suggests there is a common cause in these families and some causes cross-over between adult and pediatric ILD. These ‘cross-over’ diagnostic categories are critical for understanding the development, progression, and under-lying causes of fibrosis and other pulmonary conditions.
Figure 1: The relationship between chILD disorders and adult lung disease diagnoses. Some diagnoses are unique to each population. However, some occur in both adults and children and others are considered disease modifiers and have been implicated in altering the course of the progression of adult lung disease and should be an area of focus for combined research.
(NEHI=Neuroendocrine Hyperplasia of Infancy, PIG=Pulmonary Interstitial Glycogenosis, SFTPB=Surfactant Protein B, BOOP=Bronchiolitis Obliterans with Organizing Pneumonia, COP=Cryptogenic Organizing Pneumonia, OB=Obliterative Bronchiolitis, LIP=Lymphocytic Interstitial Pneumonia, SFTPC=Surfactant Protein C, ABCA3=ATP binding cassette protein, NSIP=Non-Specific Interstitial Pneumonia, NKX2-1=NK homeobox 1 is involved with Thyroid Transcription Factor 1, TERT=alters telomerase transcriptase (TERT) expression, DIPNECH=Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, SFTPA=Surfactant Protein A, MUC5B=variation in the MUC5B airway mucin gene, IPF=Idiopathic Pulmonary Fibrosis, UIP=Usual Interstitial Pneumonia, AIP=Acute Interstitial Pneumonitis)
Because children are not small adults and the forms of ILD are different, children who have or may have chILD should see a pediatric pulmonologist, ideally with experience in chILD. Families that have multiple generations affected should also reach out to the chILD Research Network.
While chILD disorders are rare and under-funded, the investment in chILD research has wide-ranging implications for understanding adult lung disease.