Table 1.

Clinical, biochemical and genetic findings at diagnosis in patient 1 and patient 2.

	Patient 1	Patient 2
Age of onset	18 months	Neonatal
Clinical findings	Lactic acidosis following gastro-enteritis Developmental delay	Lactic acidosis Neurological distress Hepatic failure
Laboratory investigation	pH = 6.98 Lactate: 11.3 mmol/L Increased plasma L/P ratio LCR 3-OHB/AcAc ratio in the lower range Ammonemia: 70 μmol/L	pH = 7.15 Lactate = 17 mmol/L Increased plasma L/P ratio Decreased plasma 3-OHB/AcAc ratio Ammonemia: 268 μmol/L
	Plasma amino acids:  Alanine: 298 μmol/L  Proline: 114 μmol/L  Lysine: 136 μmol/L  Glutamine: 327 μmol/L  Citrulline: 6 μmol/L	Plasma amino acids:  Alanine: 958 μmol/L  Proline: 801 μmol/L  Lysine: 713 μmol/L  Glutamine: 264 μmol/L  Citrulline: 158 μmol/L
	Urinary organic acids:  Lactic acid: 59 mol/mol creatinine  3-OHB: 45 mol/mol creatinine  Complex IV: 180 nmol/min/mg proteins	Urinary organic acids:  Lactic acid: > 75 mol/mol creatinine  3-OHB: 8359 mmol/mol creatinine  Complex IV: 223 nmol/min/mg proteins
Genetics	c. 808C>T; p.Arg270Trp c. 1892G>A; p.Tyr631Gln	c. 1023-1G>T (IVS7-1G>T); p.Asp341GlufsX351 c.911A>G; p.Tyr304Cys
Outcome	8 year-old: needs specialized school	Death at 6 months

L: lactate; P: pyruvate; 3-OHB: 3-hydroxybutyrate; AcAc: aceto-acetate; normal range: plasma ammonemia: 15–45 μmol/L; alanine: 174–375 μmol/L; proline: 93–233 μmol/L; lysine: 85–241 μmol/L; glutamine: 423–545 μmol/L; citrulline: 21–38 μmol/L; lactic acid: < 76 mmol/mol creatinine; 3-hydroxybutyrate: < 99 mmol/mol creatinine; complex IV: 308–457 nmol/min/mg of protein.