+ve mtDNA mutation % (n) | −ve mtDNA mutation % (n) | p value | |
---|---|---|---|
Sign/symptom | |||
Myopathy | 73% (11) | 27% (39) | 0.0002 |
Ataxia | 47% (7) | 28% (41) | NS |
PEO | 40% (6) | << 1% (1) | < 0.0001 |
Stroke-like episodes | 40% (6) | 20% (30) | NS |
Pigmentary retinopathy | 33% (5) | 13% (19) | 0.0354 |
Developmental delay | 33% (5) | 59% (87) | NS |
Seizures | 27% (4) | 34% (50) | NS |
Dystonia | 13% (2) | 18% (26) | NS |
Sensorineural deafness | 13% (2) | 7% (10) | NS |
Investigation (Number positive of number tested) | |||
Muscle biopsy | 90% (9 of 10) | 17% (12 of 69) | < 0.0001 |
Blood or CSF lactate | 73% (11 of 13) | 45% (66 of 135) | NS |
MRI of head | 63% (5 of 8) | 37% (38 of 104) | NS |
p value are results analysed by Fisher’s exact test.
PEO, progressive external ophthalmoplegia; CSF, cerebrospinal fluid; MRI, magnetic resonance imaging.