SOD1 and Motor neuron atrophy: Importantly, the lack of significant body weight loss and spinal motor neuron degeneration in 12-month-old SOCK mice clearly distinguishes them from transgenic mutant SOD1 mouse models used to study ALS, which exhibit robust weight loss from 3 months-of-age following progressive spinal motor neuron degeneration and muscle wasting (~ 5%/week [42]).