Furthermore, significant correlations between plasma GFAP and MMSE scores were detected in the PD-MCI (r = −0.313, P = 0.013) and PDD groups (r = −0.506, P = 0.014), but not observed in the PD-NC group (r = −0.128, P = 0.335). The gene discussed is GFAP; the disease is Parkinson disease.