Parkinson’s disease (PD), Dementia with Lewy Bodies (DLB) and Multiple System Atrophy (MSA) are adult-onset neurodegenerative disorders that result in the progressive loss of motor and/or cognitive functions and are linked to neuronal degradation, accompanied by deposition of proteinaceous aggregates, including α-synuclein (αSyn). The gene discussed is SNCA; the disease is Lewy body dementia.