Only approximately 3% to 5% among all sporadic PD cases are attributable to defects in seven PD-associated genes: SNCA (autosomal dominant pattern of inheritance; (ADPI)), LRRK2 (ADPI), EIF4G1 (ADPI), VPS35 (ADPI), parkin/PARK2 (autosomal recessive pattern of inheritance; (ARPI)), DJ-1/PARK7 (ARPI), and PINK1 (ARPI) [38], [39]. Here, SNCA is linked to Parkinson disease.