The overall prevalence of pulmonary hypertension has been estimated at 25–50 per million population: it is probably considerably less prevalent in children than in adults. Twenty years ago the estimated median survival of children with pulmonary hypertension was 2.3 years. Data about the clinical features and course of pulmonary hypertension in children have been sparse but an international study (Rolf MF Berger and colleagues. Lancet 2012;379:537–46; see also Comment, …