It has also been reported that muscle specific expression of the mutant SOD1 gene, one of the genes associated with the familial form of ALS, induces muscle atrophy, a significant reduction in muscle strength, mitochondrial dysfunction, microgliosis5 and neuronal degeneration9, thus suggesting that retrograde signals from muscle to nerve may contribute to synapse and axon damage. The gene discussed is SOD1; the disease is amyotrophic lateral sclerosis.