Accumulating evidence has demonstrated that OPN plays a significant role in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and multiple sclerosis,26, 27, 48 as well as acute brain injury including TBI, stroke, and hypoxia‐ischaemia brain injury.49, 50, 51, 52. The gene discussed is SPP1; the disease is Parkinson disease.