Additional studies show that TFAM knockout in neurons results in reduced mtDNA expression and respiratory chain deficiency in midbrain DA neurons, which, in turn, leads to a Parkinson’s-like neurodegenerative phenotype with adult-onset of slowly progressive impairment of motor function accompanied by the formation of intraneuronal inclusions and dopamine nerve cell death (Ekstrand et al., 2007). This evidence concerns the gene TFAM and Parkinson disease.