Motor neuron disease (MND) refers to conditions characterized by degeneration of upper and lower motor neurons. Amyotrophic lateral sclerosis (ALS) is the most common form of MND and involves both upper and lower motor neurons. ALS is defined clinically based on involvement of these motor neurons and leads to loss of muscle strength, atrophy, fasciculations, and difficulties with movement. The only approved treatment for ALS is riluzole, which may modestly extend survival by 2-3 months by reducing glutamate-induced excitotoxicity.