Diagram showing a hypothetic cascade of cellular events leading to neurodegeneration and neuronal death in motor neurons in ALS/FTD. This schematic diagram summarizes the key features occurring in vulnerable MNs. Resistant MNs are protected by the expression of a genes controlling cellular mechanisms that are defective in ALS/FTD (RNA dysfunction, ER stress, mitochondrial defects, protein transport dysfunction, dysregulation of neuronal excitability and excitotoxicity). These processes can be exacerbated by age, environmental and genetic mutations.