Distribution of 346 subjects in the disease categories and subcategories of the chILD-EU register after peer review
| Category | Subcategory/Diagnosis | Total | Percentage |
| A1—DPLD-diffuse developmental disorders | 9 | 2.6% | |
| Alveolar capillary dysplasia with misalignment pulmonary vein | 7 | ||
| Congenital alveolar dysplasia | 2 | ||
| A2—DPLD-growth abnormalities deficient alveolarisation | 22 | 6.4% | |
| Related to preterm birth | 11 | ||
| Related to chromosomal disorders | 8 | ||
| Others | 3 | ||
| A3—DPLD-infant conditions of undefined aetiology | 64 | 18.5% | |
| Chronic tachypnoea of infancy (usual or aberrant) | 30 | ||
| Neuroendocrine cell hyperplasia of infancy | 27 | ||
| Pulmonary interstitial glycogenosis | 5 | ||
| Others | 2 | ||
| A4—DPLD-related to alveolar surfactant region | 77 | 22.3% | |
| ABCA3 mutations | 18 | ||
| SFTPC mutation | 10 | ||
| NKX2.1 mutations | 3 | ||
| NSIP | 19 | ||
| Pulmonary alveolar proteinosis | 9 | ||
| Others | 18 | ||
| Ax—DPLD-unclear RDS in the mature neonate | 5 | 1.4% | |
| Ay—DPLD-unclear RDS in the almost (30–36 weeks) mature neonate | 9 | 2.6% | |
| B1—DPLD-related to systemic disease processes | 54 | 15.6% | |
| Sarcoidosis | 12 | ||
| Idiopathic pulmonary haemosiderosis | 6 | ||
| Storage diseases | 4 | ||
| Immune-mediated/collagen vascular disorders | 4 | ||
| Familial dysautonomia | 3 | ||
| Filamin A mutation | 3 | ||
| Langerhans cell histiocytosis | 3 | ||
| GPA—Granulomatosis with polyangiitis (Wegener) | 3 | ||
| Others | 16 | ||
| B2—DPLD-in the presumed immune intact host, related to exposures (infectious/non-infectious) | 46 | 13.3% | |
| Infectious/postinfectious processes | 17 | ||
| BO | 14 | ||
| Exogen allergic alveolitis/hypersensitivity pneumonitis | 7 | ||
| Others | 8 | ||
| B3—DPLD-in the immunocompromised host or transplanted | 15 | 4.3% | |
| NSIP | 4 | ||
| BO | 3 | ||
| Related to transplantation and rejection | 3 | ||
| Others | 5 | ||
| B4—DPLD-related to lung vessels structural processes | 16 | 4.6% | |
| Pulmonary haemorrhage | 8 | ||
| Pulmonary hypertension | 5 | ||
| Others | 3 | ||
| B5—DPLD-related to reactive lymphoid lesions | 4 | 1.2% | |
| Lymphocytic interstitial pneumonia | 3 | ||
| Others | 1 | ||
| Bx—DPLD-unclear RDS in the NON-neonate | 1 | 0.3% | |
| By—DPLD-unclear NON-neonate | 5 | 1.4% | |
| Bz—DPLD | 1 | 0.3% | |
| C1—localised, congenital gross structural abnormalities of the lungs | 6 | 1.7% | |
| C2—localised, acquired gross structural abnormalities of the lungs | 0 | 0% | |
| D—Airway disorders | 12 | 3.5% | |
| Chronic bronchitis | 7 | ||
| Others | 5 |
Cases of chronic tachypnoea of infancy (usual or aberrant) had no biopsy and were defined as described previously;16 cases were only labelled ‘Neuroendocrine cell hyperplasia of infancy’ if there was proof by biopsy and concordant clinical symptoms. Details on the classification system and definitions used are given in the supplement of Griese et al.12
BO, bronchiolitis obliterans; DPLD, diffuse parenchymal lung diseases; NSIP, non-specific interstitial pneumonitis; RDS, respiratory distress syndrome.