LRRK2 and Parkinson disease: Of the other PD-linked proteins, from highest to lowest abundance, included SNCA (α-synuclein) (~4.7 million copies per cell), Parkinson disease protein 7 homolog (PARK7/DJ1) (~1.5 million copies per cell), Vacuolar protein sorting-associated protein 35 (VPS35) (~175 thousand copies per cell), VPS13C and polyamine-transporting ATPase 13A2 (ATP13A2) (both 2 thousand copies per cell), and Leucine-rich repeat serine/threonine-protein kinase 2 (LRRK2) (~133 copies per cell).