ATM and juvenile Huntington disease: Following damage-sensing Mre11, Rad50, and Nbs1 (MRN) complex in conjunction with DNA double-strand breaks, ATM is activated to phosphorylate numerous of substrates such as KAP1, Akt, and p53 to regulate diverse cellular processes, including DNA repair, cell apoptosis, and so on [34–36].In Huntington’s disease, ATM is found to trigger mitochondrial-mediated apoptosis through activation of AMP-activated protein kinase (AMPK) [37].