The down-regulated genes can significantly affect “Parkinson’s disease,” “Huntington’s disease,” “AD,” and “Oxidative phosphorylation.” NDUFA4, NDUFB6, ATP5F1C, CALM2, COX5B, COX4I1, and CYCS are also involved in the three major neurodegenerative diseases, including Parkinson’s disease, Huntington’s disease, and AD (Stelzer et al., 2016; Adav et al., 2019). The gene discussed is CYCS; the disease is Huntington disease.