In SH-SY5Y cells and hepatocellular carcinoma cells, mitochondrial electron transport chain (ETC) function, mitochondrial cristae, and mtDNA levels were decreased when PINK1 was knocked down, indicating a critically important role of PINK1 in mitobiogenesis and in maintaining the activity of the mitochondrial ETC [223, 224]. The gene discussed is PINK1; the disease is hepatocellular carcinoma.