Canonical discriminant function 1 strongly correlated with t-α-syn (r = − 0.694*), o-α-syn (r = − 0.499*) and pS129-α-syn (r = 0.390*) and discriminated both asymptomatic LRRK2 mutation carriers and PD groups from Ctrl group; we will subsequently refer to this function as the Disease function. This evidence concerns the gene LRRK2 and Parkinson disease.