Clinical symptoms
| Children | No. |
|---|---|
| With mitochondrial dysfunction | 22 |
| Cognitive delay | 15 |
| Dystonia | 6 |
| Nonfebrile seizures | 6 |
| Severe malaise | 3 |
| Nystagmus | 2 |
| Other | 4 |
| Without mitochondrial dysfunction | 27 |
| Neurologic symptoms | 14 |
| Cognitive delay | 5 |
| Nonfebrile seizures | 3 |
| Repeated febrile seizures | 2 |
| Dystonia | 2 |
| Nystagmus | 1 |
| Acute idiopathic polyneuritis | 1 |
| Other | 2 |
| Persistent biochemical perturbations | 7 |
| Asymptomatic | 6 |