C9orf72 and amyotrophic lateral sclerosis: iPSC models of ALS have previously been used to characterize phenotypic patterns of neurodegeneration in mid-size cohorts of sporadic ALS patient iPSC-derived motor neurons derived from a population of Japanese ALS and control subjects13, and to construct disease-associated protein-protein interaction networks for ALS cases associated with the mutant C9orf72 hexanucleotide repeat expansion14.