In mouse lung, Nkx2-1 absence results in impaired branching morphogenesis, abnormal distal cell differentiation and neonatal death [5]; mutations that prevent Nkx2-1 phosphorylation result in relatively normal morphogenesis but lethal functional defects [6]; conversely, epithelial Nkx2-1 over-expression produces cell hyperplasia, disrupted alveolar septation and emphysema [7]. This evidence concerns the gene NKX2-1 and pulmonary emphysema.