A significant positive correlation between homocysteine and MDS-UPDRS III score was identified in males with Parkinson's disease (rs = 0.319, p < 0.001), but not in females, whereas a significant negative correlation between homocysteine levels and total ACE-R score was observed in females with Parkinson's disease (rs = −0.449, p < 0.001), but not in males. Here, ACE is linked to Parkinson disease.