NRTN encodes neurturin, a growth factor that supports the survival of sympathetic neurons and regulates CNS development and maintenance 1. NRTN functions by binding to its coreceptor GFRA2, leading to autophosphorylation and activation of the RET receptor, with heparan sulfate-binding required for signaling 234. Recent studies reveal NRTN's role in bone homeostasis, where it establishes a neurotrophic dependency between sympathetic cholinergic fibers and osteocytes through GFRα2-mediated signaling 5. In Parkinson's disease pathogenesis, NRTN serves as a neuroprotective factor produced by striatal interneurons and astrocytes through Hedgehog signaling, supporting dopaminergic neuron viability 67. Reduced NRTN expression contributes to disease progression when primary cilia formation is impaired by LRRK2 or GBA1 mutations 67. NRTN also shows clinical relevance in inflammatory conditions, with sputum NRTN levels correlating with Type 2 airway inflammation in asthma 8 and NRTN downregulation promoting allergic asthma through macrophage activation 9. In cancer, NRTN interacts with TANGO1 to promote hepatocellular carcinoma progression via PI3K/AKT/mTOR signaling 10. Gene therapy approaches targeting NRTN to the substantia nigra demonstrate neuroprotective effects in Parkinson's disease models 11.