In the case of PD, previous studies by our groups and others have generated iPSCs from patients with PD associated with LRRK2 mutations, and described the appearance of disease-specific phenotypes in iPSC-derived neurons, including impaired axonal outgrowth and deficient autophagic vacuole clearance (Heman-Ackah et al., 2017, Nguyen et al., 2011, Sanchez-Danes et al., 2012, Skibinski et al., 2014). This evidence concerns the gene LRRK2 and Parkinson disease.