Table 2.

Reported clinical symptoms in patients with nuclear encoded complex I deficiency, including the prevalence and mean age of presentation in our cohort (n = 130)

Clinical symptom	Prevalence	Median age of onset (months)	Range (years)
Hypotonia	60 %	5	0 – 6
Failure to thrive	34 %	6	0 – 2.8
Nystagmus	34 %	7	0 – 10
Dys- or hypertonia	32 %	12	0 – 9
Psychomotor retardation	30 %	6	0 – 6
Feeding problems	29 %	5	0 – 5.2
Pyramidal symptoms	28 %	13	0 – 13
Respiratory abnormalities	27 %	11	0 – 12
Developmental regression	25 %	11	0 – 7,5
Vomiting	22 %	7	0 – 4
Epilepsy	21 %	8	0 – 10
Cardiomyopathy	20 %	4	0 – 3
Optic atrophy	20 %	10	0 – 11
Deterioration after infections	18 %	6	0.3 – 3.2
Ataxia	18 %	24	0.5 – 8
Lethargy	18 %	6	0 – 20
Encephalopathy	16 %	6	0 – 2.5
Vision problems	17 %	6	0 – 10
Muscle weakness	15 %	8	0 – 11.6
Irritability	15 %	7	0 – 16
Extrapyramidal symptoms	15 %	14	0.3 – 10
Strabismus	14 %	7	0.1 – 6
Dysphagia	13 %	6	0 – 9
Pure motor retardation	11 %	9	0 – 2
Dystrophy	9 %	6	0.3 – 8
Myoclonic epilepsy	8 %	10	0.2 – 10
Hearing loss	8 %	16	0.1 – 10
Ptosis	7 %	16	0.3 – 2.5
Exercise intolerance	7 %	48	0 – 20
Temperature regulation problems	5 %	6	0.4 – 20
Gastrooesophageal reflux	5 %	6	0 – 1,1
Hepatopathy	4 %	4	0 – 1,3
Ophthalmoplegia	4 %	9	0.6 – 2.2
Constipation	4 %	6	0.2 – 7
Osteoporosis	3 %	78	5-16
Neuropathy	3 %	8	0.5 – 30
Tension abnormalities	2 %	51	0.5 – 8
Renal involvement	2 %	17	0.5 – 2
Retinitis pigmentosa	1 %		13