Spectrum of Diagnoses
The 683 subjects were classified by site investigators in the following
categories: lung developmental dysplasia; alveolar growth disorder;
surfactant dysfunction; pulmonary alveolar proteinosis due to other
causes; pulmonary interstitial glycogenosis; neuroendocrine cell
hyperplasia of infancy (NEHI); bronchiolitis obliterans; alveolar
hemorrhage; chILD associated with connective tissue or immune-mediated
disorders; other specific or multisystem disorders; environmental /
toxic / drug related chILD; or unclassified ILD (Table 2 ). To
date, the most frequent diagnosis is NEHI, with a total of 155 subjects
comprising 22.7% of all registry enrollment. The second most frequent
diagnosis is ILD associated with connective tissue or immune-mediated
disorders (113 subjects, 16.5%). For 11% of enrolled subjects, the
diagnostic designation was ‘unclassified ILD’ (Figure 2 ).
Within these broader categories, subclassifications or specific
diagnoses could be subsequently selected by site investigators. For
example, within the surfactant metabolic dysfunction category,
surfactant protein-C gene (SFPTC ) is most frequently reported (37
subjects; 45.1% of surfactant metabolic dysfunction category), while
ILD due to ABCA3 disruption is reported in 30 (36.6%) of
subjects. The most frequently enrolled subtype of bronchiolitis
obliterans is post-infectious (34 subjects, 45.3% of bronchiolitis
obliterans category).