Commonly misconstrued as either a variant of AD or PD, or misdiagnosed as AD or PD, Lewy body Dementia (LBD) is one of the most common causes of dementia resulting from excessive and abnormal α-synuclein deposits in the brain called Lewy bodies and is associated with cognitive aging (LB) [104-106]. The gene discussed is SNCA; the disease is Parkinson disease.