LRRK2 and Parkinson disease: While the difference was not statistically significant, there was a trend toward faster motor decline in participants with α-syn SAA positive LRRK2 PD (n = 111; 2.39 (1.86–2.92)) compared to those with α-syn SAA negative LRRK2 PD (n = 51; 1.76 (0.93–2.60); difference = 0.63 (−0.29 to 1.55), p = 0.18).