LRRK2 and Parkinson disease: Age did not affect the colonic expression of LRRK2 in these two groups (control group: r = –0.1810, 95% confidence interval: –0.4736 to 0.1477, P = 0.26; PD group: r = 0.0081, 95% confidence interval: –0.2758 to 0.2907, P = 0.96; Figure 2A).