Down syndrome and pulmonary hemosiderosis: an under-recognized association

Introduction: Pulmonary hemosiderosis is a rare cause of interstitial lung disease in children. The French experience had previously highlighted that 20% of the 25 included children also had Down syndrome (DS). In this study populations, the main features of the patients with hemosiderosis were unspecific stigmata of autoimmune disease. This study aims to investigate the relationships between pulmonary hemosiderosis and DS. Material and methods: Patients with pulmonary hemosiderosis followed is one of RespiRare network and younger than 20 years old at diagnosis were selected. The following data were collected : DS status, clinical, biological, functional, and radiological findings. Results: Nine of the 34 included patients (26%) had DS. They were a girl predominance (72%) in the non-DS group, and a male predominance in the DS group (56%). The mean age at the diagnosis was 3.80±3.30 with no significant difference between DS and non-DS patients. DS patients tended to present a more severe form of the disease with more dyspnoea (p=0.03) and more pulmonary arterial hypertension (PAH) (p=0.0003). The 3 (9%) patients who died were DS patients (p=0.0003). Discussion and conclusions: DS seem to be a risk factor for hemosiderosis. Hemosiderosis in DS patients is more severe at presentation, and at follow-up. Several hypotheses can be proposed for such association: an increased fragility of the lung capillary, a higher susceptibility to autoimmune lesions, and a higher risk of chronic hypoxia, leading to PAH. In DS, hemosiderosis should be considered in patients with anaemia of unknown origin.