Such a link is evident in X-linked parkinsonism with spasticity (XPDS), which is associated with a mutation in ATP6AP2, which causes altered splicing of this prorenin receptor, a key regulator of V-ATPase function (Table 1, Fig. 1) (Jansen and Martens, 2012; Korvatska et al., 2013). The gene discussed is ATP6AP2; the disease is X-linked parkinsonism-spasticity syndrome.