GBA1 and Parkinson disease: Potential associationsbetween the heterozygous mutations of the glucocerebrosidase encoding gene(GBA) and Parkinsonism were also described in MJD (Siebert et al., 2012), andbetween age at onset and modifiers, such as the methylation state ofATXN3 (Emmel etal., 2011) and the chaperone variants (Kuiper et al., 2017).