α-synuclein (SNCA) and leucine-rich repeat kinase 2 (LRRK2) for autosomal dominant PD, and PINK1, PARK7 (DJ-1), ATPase type 13A2 (ATP13A2), and PARK2 (parkin) for autosomal recessive PD, have been identified as the underlying genes that generate common monogenic types of PD in only six of these locations [6]. This evidence concerns the gene SNCA and Parkinson disease.