Additionally, reduced visual memory performance has also been reported in PD-free glucocerebrosidase (GBA) mutation carriers (Zokaei et al. 2014) and impaired verbal memory performance (Yilmaz et al. 2016; Holthoff et al. 1994; Chahine et al. 2015) in PD risk groups. The gene discussed is GBA1; the disease is Parkinson disease.