They found downregulation of four genes involved in oxidative stress in pre-HD and HD patients (S-adenosyl-L-homocisteine hydrolase—AHCsY-, aconitase 2-ACO2-, 3-oxoacid CoA transferase 1-OXCT1-, and adenylyl cyclase-associated protein 1-CAP1) and downregulation of the Uncoupling protein 2 (UCP2) gene in HD patients only. This evidence concerns the gene ACO2 and Huntington disease.