SNCA and Parkinson disease: These findings require further research, however, it is important to point out that: (1) it is important to study how, in mature synapses, sequestration of normal α-synuclein from the presynaptic terminal into abnormal aggregates contributes to neuronal dysfunction; and (2) studies utilizing models in which α-synuclein (normal or mutant) is overexpressed may not recapitulate what occurs in a PD brain with endogenous (or only slightly higher) levels of α-synuclein.