It is difficult to study mitochondrial morphology in PD patients because the ultrastructure of post-mortem brain tissue of PD patients are not well preserved; however, PD-related neurotoxins can cause DRP1-dependent mitochondrial fragmentation in vivo and in vitro, indicating that mitochondrial fusion and fission are involved in PD (Santos and Cardoso, 2012). This evidence concerns the gene DNM1L and Parkinson disease.