Haploinsufficiency for NKX2‐1 due to either complete gene deletions or loss‐of‐function mutations results in brain–thyroid–lung syndrome with affected individuals having variable degrees of pulmonary disease (neonatal respiratory distress syndrome or children's interstitial lung disease), hypothyroidism, and neurologic abnormalities (typically benign hereditary chorea) 6, 7, 8, 9, 10, 11. This evidence concerns the gene NKX2-1 and interstitial lung disease.