GBA1 and Parkinson disease: Penetrance of GBA1 mutations is variable and age dependent; a cumulative risk of developing PD of 5% and 10–30% is observed by 60 and 80 years of age, respectively, in heterozygous carriers when compared to controls (Anheim et al. 2012; Rana et al. 2013; Balestrino et al. 2020).