MCAT and Leigh syndrome: Our results also showed higher survival compared with a previous MT-ATP6 cohort study12 or natural history studies on LS including patients with MT-ATP6 defects, reporting a survival between 64% and 74% in patients.11 However, those data have the limit of being retrospectively collected, and prospective studies are needed to confirm the survival rate of patients with MT-ATP6/8 defect.