B3GALT4 and Parkinson disease: Similar to what was observed for B3GALT4 expression, there was a significant decrease in ST3GAL2 expression in residual neuromelanin-containing cells in the SN of PD patients (6.0 ± 0.4 dots/cell, n = 7) compared to neurologically normal controls (12.5 ± 1.1 dots/cell, n = 8) (t = 5.532, df = 14, P < 0.0001) (Fig 3A and 3B).