NPTX2 and maternally-inherited Leigh syndrome: For example, the mtDNA T8993G (NARP) mutation has been shown to inhibit oxidative phosphorylation in both NARP (neuropathy, ataxia, and retinitis pigmentosa) (Holt et al., 1990) and MILS (maternally inherited Leigh’s syndrome) (Santorelli et al., 1993) resulting in increased ROS levels and free radical damage.