Summary of clinical diagnosis and MR spectroscopy results

Patient No.	Sex	Age (yr)	Clinical Syndrome	Supportive Data	MR Spectroscopy Findings
					Lactate		Site Interrogated
					CSF	Brain	Site Interrogated
Group 1: well-established diagnosis
1	M	29	Kearns-Sayre	Large mtDNA deletion on muscle biopsy	N/A	−	Left mesial frontal lobe (STEAM)
5	M	31	MELAS	Point mutation mitochondrial tRNA (Leu)	N/A	+	Small right parietal lesion, more Lac in control left side (STEAM)
					+	+	Second MR spectroscopy 3 yr later: gray > white matter stroke-like lesions (MRSI)
7	M	37	MERRF	Abundant RRF on muscle biopsy	N/A	−	Left front and occipital, 3 cm single voxel (STEAM)
10	M	7	MELAS	Muscle biopsy: RRF, mitochondrial tRNA point mutation, serum Lac 2.9	N/A	+	Left frontal white matter, single voxel (STEAM)
					N/A	+	Second MR spectroscopy 3 mo later: left frontal, smaller after vitamin treatment in 2 days (STEAM)
12	M	1	Elevated Lac	Serum Pyr 1.4–2.4^, Lac 1.0–3.2^	N/A	+	Left basal ganglia, single voxel (STEAM)
18	M	3	MELAS/MERRF overlapping syndrome	Mitochondrial DNA point mutation	−	−	(MRSI)
				1995 normal Lac, Pyr, 1998 Pyr 1.1^, Lac 3.4^	+	+	2nd MR imaging 11 months later: (MRSI), periventricular white matter
26	F	8	Complex I mitochondrial disease	Diagnosed at age 3 yr	+	+	Frontal white matter, corpus callosum lesions (MRSI)
32	M	13	Leigh disease	Elevated CSF Lac and Pyr	N/A	−	Post parietal gray and white matter, thalami, single voxel (PRESS)
Group 2: possible diagnosis
3	F	27	GI disturbances, “leukodystrophy” pattern white matter abnormality	Abnormal ultrastructure of mitochondria on intestinal muscle biopsy	N/A	−	White matter abnormality (STEAM)
4	F	6	Multiple stroke-like episodes	Muscle biopsy normal	N/A	−	Deep white matter lesions (STEAM)
8	M	8	Suspected Leigh disease	Basal ganglia abnormality, negative CSF Lac	N/A	−	Left high cortical region (STEAM)
9	F	0.5	Developmental delay, poor vision, global cerebral Lac acidosis	Diffuse cortical atrophy, decreased white matter volume and hypomyelination	N/A	+	Left frontal cortex, single voxel (STEAM)
11	M	37	“Occipital stroke,” suspected MELAS		N/A	−	Left and right occipital lobes, single voxel (PRESS)
13	F	2	Progressive ataxia, encephalitis-like symptoms		+	+	Basal ganglia (MRSI)
15	M	2	Suspected MELAS, peri-varicella encephalocerebellitis, progressive myoclonus	Serum Lac and Pyr, elevated CSF Lac normal, muscle biopsy normal	−	−	(MRSI)
17	M	13	ADEM, 2 episodes	Serum Lac normal	−	−	(MRSI)
19	M	1	Lennox-Gastaut with myoclonic epilepsy, cerebral palsy		+	−	(MRSI)
21	M	1	Probable neurodegenerative disease, seizure, mental retardation, failure to thrive	Serum Lac 2.6–3.1^*, abnormal fatty acid oxidation	−	−	(MRSI)
22	M	3	Developmental delay, seizure, progressive spasticity		−	−	(MRSI)
24	F	17	Progressive spastic paraparesis, ataxia	Serum Lac 1.2, Pyr 0.3	−	−	(MRSI)
28	F	21	Relapsing subacute encephalopathy, suspect Leigh disease	History of elevated serum Lac and Pyr	−	−	(MRSI)
29	M	7	Suspected MELAS		−	−	(MRSI)
30	M	12	Movement disorder with seizures		+	+	Left anterior medial temporal lobe T2-hyperintense lesions (MRSI)
31	M	32	Suspected MELAS, mental retardation, mitochondrial encephalopathy		−	−	(MRSI)
Group 3: diagnosis excluded by other data
20	M	8	Cerebral palsy w/choreoform movements, probable guanidinoacetate N-methyltransferase deficiency	Skin biopsy EM normal	−	−	(MRSI)
23	M	7	Cerebral palsy with spastic diplegia		−	−	(MRSI)
25	F	30	Developmental delay, bipolar syndrome	Laboratory results normal	−	−	(MRSI)
27	F	39	Carbohydrate metabolic disease, stroke, endocrine abnormalities, hyperreflexia, poor coordination		−	−	(MRSI)
33	F	20	Acquired lipid myopathy and sensory axonal neuropathy	Biochemical ETF-QO deficiency with defined mutation	−	−	(MRSI)

Note.—Age indicates patient age in years at time of presentation; Clinical Syndrome, diagnoses made clinically in conjunction with biochemical, genetic, and/or histologic tests (if no final diagnosis available, presenting clinical symptoms listed); M, male; F, female; mtDNA, mitochondrial DNA; N/A, not available; +, presence of lactate; −, absence of lactate; STEAM, stimulated-echo acquisition mode; MELAS, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes; tRNA (Leu), transfer RNA leucine; Lac, lactate; MRSI, MR spectroscopic imaging; MERRF, myoclonus, epilepsy, and ragged red fibers; RRF, ⧫; tRNA, transfer RNA; Pyr, pyruvate;
* , abnormal laboratory value; MELAS/MERRF, overlap of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes with myoclonus, epilepsy, and ragged red fibers; PRESS, point-resolved spectroscopy; GI, gastrointestinal; ADEM, acute disseminated encephalomyelitis; ETF-QO, electron transfer flavoprotein ubiquinone oxidoreductase.
⧫. In general, CSF data were obtained from the MRSI records only.