PD and PD-like syndromes associated with GBA mutations were first described in 1996 [107], and have subsequently been demonstrated to occur at much higher frequencies in PD patients than controls in pan-ethnic populations from Israel [108,109], Italy [110], China [111,112], North Africa [113], Great Britain [114], Europe [115], and the United States [116,117]. This evidence concerns the gene GBA1 and Parkinson disease.