CEACAM5 and Parkinson disease: Regarding the CEA, consistent with our results (Figure 3H), one cross-sectional study (Akil et al., 2015) including 51 PD patients and 50 healthy controls reported that the CEA was significantly higher in PD relative to the control group (mean 2.40 ± 1.51 vs. 1.72 ± 0.87 (ng/mL), p = 0.015).