{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Paired-like homeobox 2b (PHOX2B) is a transcription factor that regulates the expression of genes involved in neuronal specification, migration, and survival during embryonic development. PHOX2B is particularly important for the development of the autonomic nervous system, including sympathetic and parasympathetic ganglia, as well as the enteric nervous system in the gastrointestinal tract. Mutations in the PHOX2B gene have been implicated in the pathogenesis of congenital central hypoventilation syndrome (CCHS), Hirschsprung"},{"type":"text","value":"'"},{"type":"text","value":"s disease, and neuroblastoma. PHOX2B mutations may disrupt normal neuronal development and contribute to the malignant transformation of neural crest-derived precursor cells into neuroblastoma cells."}]}]}