Table 1.

Scores of the patient on the Mitochondrial Disease Criteria with an explanation of the positive findings.

Mitochondrial Disease Criteria		Score	Comment
Muscular	Myopathy	1	Fatigue, mild weakness, muscle atrophy, myopathological changes in biopsy
Max. score is 2	Abnormal EMG	0
	Motor developmental delay	0
	Exercise intolerance	1
Neurological	Developmental delay or ID	1	Learning difficulties
Max. score is 2	Speech delay	1
	Dystonia	0
	Ataxia	0
	Spasticity	0
	Neuropathy	0
	Seizures or encephalopathy	0
Multisystem	Gastrointestinal tract disease	0
Max. score is 3	Growth delay or failure to thrive	1	Failure to thrive, growth difference in the lower limbs
	Endocrine	1	Testosterone deficiency
	Immune	0
	Eye (vision) or Hearing	0	Tinnitus
	Renal tubular acidosis	0
	Cardiomyopathy	0
Total maximal clinical score is 4		1 + 2+2 reaches total score: 4
Metabolic	Lactate high at least 2x (score:2)	2
	Alanine high at least 2x	n/a	Not measured
	Krebs cycle intermediates	n/a	Not measured
	Ethylmalonic and methylmalonic acid	n/a	Not measured
	3 methyl glutaconic acid	n/a	Not measured
	CSF lactate, alanine	n/a	Not measured
Imaging and other	Leigh disease (score: 2)	0
	Stroke-like episodes (score:2)	0
	Lactate peak on MRI	0
	Leukoencephalopathy with brainstem and spinal cord involvement	0
	Cavitating leukoencephalopathy	0
	Leukoencephalopathy with thalamus involvement	0
	Deep cerebral white matter involvement and corpus callosum agenesis	0
Total maximal metabolic and MRI score is 4		Total metabolic and MRI score: 2
Total MDC score (clinical, metabolic, imaging)		Total MDC score is 6 (probable mitochondrial disorder)
Total score is maximal 8

The table indicates the subscales and the assessed scores of the MDC. MDC, Mitochondrial Disease Criteria. A score of 1 indicates unlikely mitochondrial disorder, a score of 2–4 indicates possible mitochondrial disorder, and a score of 5–7 indicates probable mitochondrial disorder. A total score of 8 is a definite mitochondrial disorder.