OPA1 and Parkinsonism: Although the majority of individuals with OPA1-related diseases have symptomatic optic neuropathy, other rare associations with spastic paraplegia (Carelli et al., 2015; Verny et al., 2008; Yu-Wai-Man et al., 2010), and syndromic parkinsonism and dementia (Carelli et al., 2015), reported severe defects in early neurogenesis due to depletion of neural progenitor cells or cortical specification (Inak et al., 2019; Romero-Morales et al., 2020) suggest that OPA1 function is essential in many areas of the central nervous system, particularly the cortex.