Table 2

Diagnostic criteria in the 31 patients with proved mitochondrial disorders

OXPHOS/PDH deficiencyMt-DNA mutationMuscle histopathologyAbnormal electron microscopySuggestive organic aciduriaAfflicted sibling
1LeighComplex VT8993G
2LeighPDH E1
4LeighComplex I3-MGA
5NARPT8993GPatient 6
6NARPT8993GPatient 5
7MiMyCaComplex IRRFYes
11E3 deficiencyPDH E3
12E3 deficiencyPDH E3
14Costeff3-MGAPatient 15
15Costeff3-MGAPatient 16
16Anaemia + myopathyComplex I + IVYes
17IPO + NBComplex IVNo COX stainingPatients 18,19
18IPO + NBPatients 17,19
19IPO + NBPatients 17,18
20EncephalopathyComplex I
21EncephalopathyComplex I
22EncephalopathyComplex IPatient 23
23EncephalopathyPatient 22
24EncephalopathyComplex I
25EncephalopathyComplex I + III + IVYes
26EncephalopathyComplex I
27EncephalopathyComplex I
28EncephalopathyComplex IYes
29EncephalopathyComplex II3-MGA
30EncephalopathyComplex I
31EncephalopathyPDH E1 + generalised
  • Generalised refers to a generalised deficiency of all respiratory chain enzymes.

  • COX, cytochrome C oxidase (complex IV); IPO + NB, intestinal pseudo-obstruction and neurogenic bladder; LHON, Leber’s hereditary optic neuropathy; 3-MGA, 3-methylglutaconic aciduria; MiMyCa, maternally inherited myopathy and cardiomyopathy; Mt-DNA, mitochondrial DNA; NARP, neuropathy, ataxia, retinitis pigmentosa; PDH, pyruvate dehydrogenase; OXPHOS, oxidative phosphorylation or respiratory chain enzymes; RRF, ragged red muscle fibres.