Table 1

Clinical phenotype and biochemical studies performed in patients with coenzyme Q₁₀ deficiency

Patient/cells*	Clinical phenotype	Biochemical studies (% with respect to mean reference values)	Effect of CoQ₁₀ supplementation†	Reference as cited in the text	Array and epigenetic code
Human dermal skin fibroblast	Healthy volunteers	Reference values	Reference values	12	#2 #HDF #control
12-year-old girl	Ataxia and cerebellar atrophy Secondary CoQ₁₀ deficiency	17% CoQ₁₀ in muscle 31% mt-RC complex I+III (muscle) 46% mt-RC complex II+III (muscle) 22% CoQ₁₀ in fibroblast 24% CoQ₁₀ biosynthesis rate ROS production (three fold)	Improvement of neurological assessment No biochemical studies performed	4	#1
33-month-old boy(his sister below)	Corticosteroid-resistant nephropathy Progressive encephalomyopathy COQ2 gene mutation (c.890A>G) Primary CoQ₁₀ deficiency	23% CoQ₁₀ in muscle 19% mt-RC complex I+III (muscle) 32% mt-RC complex II+III (muscle) 17% CoQ₁₀ in fibroblast 10% CoQ₁₀ biosynthesis rate 57% mt-RC complex II+III (cells)	Improvement of neurological assessment but not the renal dysfunction Recovery of cell growth Improvement of 35% complex II+III (cells)	5 17 12 case 3	#3
9-month-old girl(her brother above)	Corticosteroid-resistant nephropathy COQ2 gene mutation (c.890A>G) Primary CoQ₁₀ deficiency	29% CoQ₁₀ in fibroblast 15% CoQ₁₀ biosynthesis rate 60% mt-RC complex II+III (cells)	Improvement of 25% complex II+III (cells) Recovery of cell growth	17 12 case 4	#5
Boy	MELAS (A3243G mutation) Secondary CoQ₁₀ deficiency	58% CoQ₁₀ in fibroblast 35% mt-RC complex I (cells) 41% mt-RC complex II+III (cells) 12% mt-RC complex IV (cells) 60% mt-ΔΨ 70% mitochondrial mass ROS production (>2-fold) Defective autophagosome elimination	Recovery of mt-RC Recovery of ATP production No ROS production	8	#4 #MEL+Q
10-day-old boy	mtDNA depletion syndrome Neonatal encephalopathy Secondary CoQ₁₀ deficiency	20% CoQ₁₀ in muscle 32% mt-RC complex I+III (muscle) 19% mt-RC complex II+III (muscle) 15% CoQ₁₀ in fibroblast 85% mt-RC complex II+III (cells)	Improvement of 41% complex II+III (cells) Recovery of cell growth	34	#ELO #ELO+Q
3-year-old boy	Dysmorphic features Ventricular septal defect and weakness Hypotonia and hyporeactivity Moderate mental retardation COQ4 gene deletion Primary CoQ₁₀ deficiency	40% CoQ₁₀ in fibroblast 44% CoQ₁₀ biosynthesis rate 64% mt-RC complex I+III (cells) 58% mt-RC complex II+III (cells)	Improvement in muscle tone and strength He began to speak and walk	18	#GIO
Girl	COQ4 gene mutation (c.483G>C) Rhabdomyolysis Primary CoQ₁₀ deficiency	18% CoQ₁₀ in fibroblast	Recovery of both complex I+III activity and growth of fibroblasts	This paper	#SIL+Q#epi
Girl	Ataxia Secondary CoQ₁₀ deficiency	38% CoQ₁₀ in fibroblast	Improvement of ATP synthesis	12 case 1	#SOF+Q#epi

*Cultured at 37°C using DMEM 1 g/l glucose, l-glutamine, pyruvate (Invitrogen) plus antibiotic/antimycotic solution (Sigma) and 20% fetal bovine serum (FBS, Linus).
†CoQ₁₀ prediluted in FBS was added to the plates at a final concentration of 30 µM (coenzyme Q₁₀, Synthetic Minimum 98%, high-performance liquid chromatography, Sigma).
CoQ₁₀, Coenzyme Q₁₀; MELAS, mitochondrial encephalopathy, lactic acidosis and stroke-like episodes; mtDNA, mitochondrial DNA; mt-RC, mitochondrial respiratory chain; ROS, reactive oxygen species.