The disorders with tauopathies are commonly accompanied with parkinsonian signs,50 while disorders with synucleinopathies are commonly attended by dementia.24 Tau aggregates have been described in familial PD linked to A53T α-syn mutation51–53 and in LRRK2 G2019S variant carriers.38 Our observations demonstrate that all MMD-LB cases have both pathologies as well as, in our cohort, the vast majority of sporadic PD cases. The gene discussed is LRRK2; the disease is dementia.