Typically, iPSCs are used to model diseases with genetic origins, such as ALS (SOD1 mutation), familial PD (mutations in Parkin and PINK1), and HD (HTT mutation), yet many sporadic forms of these and other diseases occur with increasing age, such as sporadic PD, ALS, and progressive MS (PMS; Niccoli and Partridge, 2012; Reeve et al., 2014). Here, PRKN is linked to amyotrophic lateral sclerosis.