For example, m.8993T > G (m.8993T > C) mutation; a mutation that affects mt-DNA encoded ATP synthase 6 (ATPase 6) gene, when present in low abundance only results in NARP (neurogenic muscle weakness, ataxia, and retinitis pigmentosa), while a high abundance of the same mutation results in MILS (Maternally Inherited Leigh’s Syndrome) with rapid lethalities (Iyer et al., 2012). Here, MTATP6P1 is linked to maternally-inherited Leigh syndrome.