However, when analyzing PD associated with GBA mutations in a group, patients with PD and GBA mutations exhibited a 1.7– 6-year earlier age of onset than those with idiopathic PD (Aharon-Peretz et al., 2004; Clark et al., 2007; Neumann et al., 2009; Nichols et al., 2009). This evidence concerns the gene GBA1 and Parkinson disease.