MT-ND5 and Huntington disease: Specifically, in the NADH dehydrogenase, the gene expressions of the NADH-ubiquinone oxidoreductase chain 1 (ND1, Unigene0047513), ND3 (Unigene0049019), ND4 (Unigene0037950), and ND5 (Unigene0037950) were significantly downregulated in the HD group, while the expressions of NADH dehydrogenase (ubiquinone) Fe-S protein 4 (NDUFS4, Unigene0028518), NDUFS8 (Unigene0009353), NDUFA5 (Unigene0001753), and NDUFA10 (Unigene0036514) were significantly upregulated.