A subset of PD patients carrying a highly penetrant LRRK2 mutation, such as G2019S, R1441C/G, Y1699C, or I2020T, did not show LBs or α-synuclein pathology [120,123,124,125,126,127], despite the loss of DA neurons in SNpc [120]. Here, LRRK2 is linked to Parkinson disease.