DNMT3A and amyotrophic lateral sclerosis: In the current study, we demonstrate that Dnmt3a and 5mC are in mitochondria of adult mouse and human tissue types that are mostly excitable tissues (nervous and muscle) and that tissue Dnmt3a levels are reduced and 5mC immunoreactivity accumulates in skeletal muscle myofibers and spinal cord motor neurons in mouse models of ALS.