SNCA and Parkinson disease: Copy number variations (CNVs), particularly in PRKN and SNCA, have also been highlighted to play a vital role in the development of heritable or sporadic PD (Konno et al., 2016; Mok et al., 2016; Taghavi et al., 2018) and several genes, such as ATP13A2 (Ramirez et al., 2006), PLA2G6 (Paisan-Ruiz et al., 2009), FBXO7 (Di Fonzo et al., 2009), PRKN (Djarmati et al., 2004; Lucking et al., 2000), PINK1 (Bonifati et al., 2005; Kumazawa et al., 2008), and PARK7 (Djarmati et al., 2004) were reported to be strongly associated with an early-onset age of PD (Searles Nielsen et al., 2013).