Table 1. Case information for patients with mitochondrial disease.

Patient #	Sex	Age at biopsy	Genetic diagnosis	Heteroplasmy (if applicable)	% deficiency	% RRF	CK (IU/L)	Lactate (mmol/L)	Clinical phenotype	Diagnostic notes
1	F	47	Large-scale single mtDNA deletion	N/A	20	10	226	2.4	CPEO, proximal myopathy	—
2	F	62	Large-scale single mtDNA deletion	34	20	15	122–197	2.1–3.1	CPEO, proximal myopathy	—
3	F	70	Large-scale single mtDNA deletion	22	18	9	318–1238	1.4–2	CPEO, proximal myopathy	Asymmetric myopathy
4	F	22	m.8344A>G	97	97	10	145–291	7.4	Axial, proximal myopathy, lactic acidosis	—
5	F	50	m.8344A>G	63	22	7	43	1.6	Mild myopathy	Mother of patient 4
6	F	20	m.8344A>G	40	COX intermediate	0	267	1.2	Asymptomatic	Sister of patient 4
7	F	69	m.3243A>G	21	3	2	180–375	1.3	Diabetes mellitus, deafness, gut dysmotility	—

N/A: non-available; % COX: proportion of myofibers with cytochrome c oxidase deficiency; RRF: ragged red fibers; CK: creatine kinase; CPEO: chronic progressive external opthalmoplegia; HCM: hypertrophic cardiomyopathy; OA: optic atrophy; MERRF: myoclonic epilepsy with ragged red fibers. Deletions position and sizes for patient 1: N/A; patient 2: m.8482-13460, 4978 bp; patient 3: m.8576-12968, 4392 bp. Normal clinical range for CK: 25–200 IU/L; lactate: <2.2 mmol/L. All biopsies from the tibialis anterior muscle.