Genetic Causes and Clinical Features of Childhood Interstitial Lung Diseases in China

Children Interstitial lung disease (chILD) is a heterogeneous group of rare respiratory disorders of known and unknown etiologies that are mostly chronic and associated with high morbidity and mortality. ILD are characterized by inflammatory and fibrotic changes of the lung parenchyma structure that typically result in the presence of diffuse infiltrates on lung imaging, and abnormal pulmonary function tests with evidence of a restrictive ventilatory defect and/or impaired gas exchange.

Genetic factors are important contributors to chILD. Genetic variations have been mainly described in genes encoding (or interacting with) the surfactant proteins (SP): SP-C (SFTPC) and the ATP-binding cassette-family A-member 3 (ABCA3) (ABCA3), and less frequently in the genes encoding NKX homeobox 2 (NKX2)-1 (NKX2-1), SP-B (SFTPB), SP-A (SFTPA) ,MARS and other genes.

To investigate genetic defects and clinical features of chILD in China, wide recruitment and interdisciplinary critical peer review of all diagnoses from discharge diagnosis coding system of Children's Hospital of Fudan University will be included. Each case will be given a diagnosis independently; if no firm diagnosis is possible, the investigators will review the case periodically as new information becomes available. During the first year of the study, clinicians´ decisions according to clinical practice and outcomes will be independently monitored and assessed.

The investigators will systematically optimize and clarify the relative weight of a large spectrum of single and composite clinical outcomes, sequential limited chest CT (to minimise radiation exposure), lung function testing, histopathological categorization of lung biopsies, serum markers and genetic tests. Variability, reproducibility and the effects of training on reading images will be investigated.

This project will analyse in detail treatment and outcomes within and between subjects using data collected. Analysis of the collected data will support the definition of trial protocols planned in the future.

Inclusion criteria

• The chILD syndrome exists when a child with DLD has had the common causes of DLD excluded as the primary diagnosis and has at least three of the following four criteria: (1) respiratory symptoms (e.g., cough, rapid and/or difficult breathing, or exercise intolerance);(2) respiratory signs (e.g., resting tachypnea, adventitious sounds, retractions, digital clubbing, failure to thrive, or respiratory fail- ure); (3) hypoxemia; and (4) diffuse abnormalities on CXR or a CT scan.

Exclusion criteria

• These include cystic fibrosis, congenital or acquired immunodeficiency, congenital heart disease, bronchopulmonary dysplasia, pulmonary infection, primary ciliary dyskinesia presenting with newborn respiratory distress and recurrent aspiration.