FUS and amyotrophic lateral sclerosis: Also, ALS associated FUS mutants such as R521L, R521G, R521H, R521C, P525L and R495Qfs527X have been shown to induce shortening and fragmentation of mitochondria39–44 and studies involving human WT FUS transgenic mice showed motor neuron loss16 coupled with abnormalities in mitochondrial vacuolation and a loss of synaptic vesicles45.