MAPT and Parkinson disease: In this study, we found significant correlations between extra-basal ganglia structure R2* and QSM values and autonomic dysfunction and sleep problems, and our results are in line with those of previous studies—early-stage PD patients exhibited significant loss of right amygdala gray matter density, which was correlated with the SCOPA-Aut score [35]; more severe alpha-synuclein and tau pathologies were observed in the amygdala of PD patients with sleep disturbances [36]; and blood pressure variability was associated with hippocampal volume [37].