Taken together, these observations of varying protein and mRNA levels of mitochondrial markers in both animal models and patients, particularly in the spinal cord and skeletal muscle of individuals with SOD1 mutations, indicate a potential disruption in the mitochondrial biogenesis process affecting the cellular capacity to maintain a healthy network of functional mitochondria, which further underscoring mitochondrial relevance in ALS pathogenesis. This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.