The elevated mitochondrial fission observed in AD neurons and the increased levels of proteins involved in RAB7A GTPase-TBC1D15-FIS1 MCS formation and dynamics (Figure 3), which was reported to regulate fission, may indicate a higher frequency of mitochondria–lysosome MCSs as a consequence of a dysregulation in the communication between organelles through these sites. The gene discussed is FIS1; the disease is Alzheimer disease.