Interestingly, these changes were observed in fALS motor neurons harboring SOD1, TDP43, and C9orf72 mutations; however, a study utilizing patient iPSCs with mutations in the ALS-causing gene FUS found no changes in metabolic respiration in comparison to isogenic controls, proposing a gene-specific metabolic response [96]. This evidence concerns the gene FUS and amyotrophic lateral sclerosis.