Moreover, other environmental factors that contribute to sporadic models of PD, including neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) [30, 31] and 6-hydroxidopamine [31], as well as human Lewy bodies containing α-synuclein [32], have been shown to elevate lysosomal pH in both cellular and mouse models. The gene discussed is SNCA; the disease is Parkinson disease.