NKX2-1 and respiratory system disorder: In severe cases, disrupted lung development is a likely mechanism for the respiratory disease.7 Histopathology findings support the hypothesis that disruption of NKX2.1 targets functional and structural lung development and surfactant homeostasis.7-10 The finding of ground glass opacities on chest CT scan in our patient and his continued respiratory distress may be explained by NKX2.1 gene dysfunction and correlated to decreased surfactant production resulting from altered protein metabolism.6