Patient, gender Reference Clinical presentation Age of onset Blood lactate (normal <2.5mM) Brain abnormalities Age at death Variants 1, M Kirby et al, 2004 Lethal infantile mitochondrial disease neonatal 12.0 no 6 d 4175pb deletion encompassing exons 3 and 4 homozygous 2a, F Kirby et al, 2004 Lethal infantile mitochondrial disease neonatal 6.4 no 11 d c.186+2T>A homozygous 2b, F Kirby et al, 2004 Lethal infantile mitochondrial disease neonatal 6.7 no 6 d c.186+2T>A homozygous 3a, F Spiegel et al, 2009 Lethal infantile mitochondrial disease neonatal NA NA 8 d c.344G>A (p.Cys115Tyr) homozygous 3b, M Spiegel et al, 2009 Lethal infantile mitochondrial disease neonatal 6-11.2 no 8 d c.344G>A (p.Cys115Tyr) homozygous 4a, F Spiegel et al, 2009 Lethal infantile mitochondrial disease neonatal elevated NA 6 d c.344G>A (p.Cys115Tyr) homozygous 4b, F Spiegel et al, 2009 Lethal infantile mitochondrial disease neonatal 16.8 NA 8 d c.344G>A (p.Cys115Tyr) homozygous 5, NA Swalwell et al, 2011 Lethal infantile mitochondrial disease neonatal NA NA NA p.Val63Glufs*9 homozygous 6, NA Haack et al, 2012 Muscular hypotonia < 6 months elevated no – c.352C>T (p.Gln118*) homozygous 7, F Pronicka et al, 2016 Lethal infantile mitochondrial disease neonatal NA No NA c.313_315delAAAG (p.104Lys_106Thrfs) ; c.334_359del26ins13 (p.Glu112 fs) 8, NA Ogawa et al, 2017 Leigh syndrome NA NA NA NA c.309+5G>A;
c.343T>C (p.Cys115Arg)
9, M Rouzier et al, 2019 Leigh syndrome 4 months 4.74 Leigh syndrome 11 m c.309+5G>A;c.343T>C (p.Cys115Arg)