Mutations in NKX2-1, which encodes thyroid transcription factor-1, regulating the transcription of surfactant proteins and ABCA3, as well as many other lung proteins, was found to be associated with ILD in the context of “brain-thyroid-lung” syndrome (neurological symptoms, peripheral hypothyroidism, and f-ILD). Here, NKX2-1 is linked to peripheral hypothyroidism.