ALS2 and motor neuron disorder: ALS2 is a causative gene for a juvenile autosomal recessive form of motor neuron diseases (MNDs) [4], [5], [6], including amyotrophic lateral sclerosis 2 (ALS2) [7] (OMIM 205100), juvenile primary lateral sclerosis (PLSJ) [8] (OMIM 606353), and infantile-onset ascending hereditary spastic paralysis (IAHSP) [9] (OMIM 607225).