A study found that GPNMB levels were elevated in the substantia nigra of PD patients with decreased GCase activity and increased glycosphingolipids, whereas transgenic mice modeling synucleinopathy did not show these changes, suggesting that GPNMB elevation is related to lipid-induced degeneration rather than α-syn load [53]. The gene discussed is GPNMB; the disease is synucleinopathy.