Parts of the double hit have been used in PD mouse genetic models of low VMAT activity (Miller et al., 2001; Bohnen et al., 2006; Miller et al., 1999; Okamura et al., 2010; Tong et al., 2011) or ALDH knockout mice (Wey et al., 2012; Galter et al., 2003; Grünblatt et al., 2010; Mandel et al., 2005; Molochnikov et al., 2012; Werner et al., 2008), but no animal model demonstrating DOPAL accumulation concurrent with evidence for the double hit has been reported to date. The gene discussed is LDHA; the disease is Parkinson disease.