Enrichment analysis of the 270 marker mRNAs in cluster 4 showed that their functions were significantly enriched in oxidative phosphorylation, ATP metabolic process, nucleoside triphosphate metabolic process, mitochondrial protein complex, mitochondrial inner membrane, inner mitochondrial membrane protein complex, NADH dehydrogenase activity, Parkinson disease, oxidative phosphorylation, and Huntington disease (Figure 7(c)). Here, ENSG00000251605 is linked to Huntington disease.