Lipid perturbations may be the main driver also in sporadic PD cases, and due to additional genetic contributions (see above), and/or manifesting in an age-dependent manner, since decreased GBA activity and increased glycosphingolipid levels have been described in the brain with increasing age (Rocha et al., 2015; Hallett et al., 2018). Here, GBA1 is linked to Parkinson disease.