Recently, a research group focused on elucidating how alterations in mtDNA-CN are related to cardiovascular disease generated a stable heterozygous TFAM knockout in HEK293T cells and showed a fivefold reduction in the expression levels of TFAM, a marked reduction in protein production (>81%), and an 18-fold reduction in mtDNA-CN [37]. The gene discussed is TFAM; the disease is cardiovascular disorder.