A genome-wide transcriptional analysis of muscle biopsies from 119 sarcopenic elderly men and age-matched controls showed that sarcopenia is characterized by transcriptional mitochondrial dysfunction in skeletal muscle cells, with downregulated expression of genes of oxidative phosphorylation, proteostasis, and PGC-1α/Estrogen related receptor α (ERRα)-dependent signaling, resulting in a reduced number of mitochondria, decreased activity of respiratory complexes, and low NAD+ levels [130]. This evidence concerns the gene PPARGC1A and sarcopenia.