NKX2-1 and hyperinsulinemic hypoglycemia, familial, 4: SP disorders may result in alveolar proteinosis and include surfactant protein B deficiency (SP-B), surfactant protein C deficiency (SP-C), and mutation in the genes encoding adenosine triphosphate binding cassette protein member A3 (ABCA3) and thyroid transcription factor (NKX2.1).