a disease of the motor tracts of the lateral columns and anterior horns of the spinal cord, causing progressive muscular atrophy, increased reflexes, fibrillary twitching, and spastic irritability of muscles; associated with a defect in superoxide dismutase. A number of cases are inherited as an autosomal dominant trait [MIM*105400]. This disorder affects adults, is 9095% sporadic in nature, and is usually fatal within 2 to 4 years of onset. Variants include progressive spinal muscle atrophy, in which only a lower motor neuron component occurs, and progressive bulbar palsy, in which isolated or predominantly lower brainstem motor involvement is seen. Syn: Aran-Duchenne disease, Charcot’s disease, creeping palsy, Cruveilhier’s disease, Duchenne-Aran disease, Lou Gehrig’s disease, muscular trophoneurosis, progressive muscular atrophy, progressive spinal amyotrophy, wasting palsy, wasting paralysis.