Table 1. Comparison of the two Finnish patients to 22 previously reported patients6, 7, 8, 9, 10.
| Previously reported patients (22) | Age of death for Patient 1 | Age of death for Patient 2 | |
|---|---|---|---|
| Age of onset | 0–4 months | 5mo | 6mo |
| Current age | 1.2–16y (11/20) | 9y | 20y |
| Age of death | 0.8–21y (9/22) | − | − |
| Intra-uterine growth retardation | 2/2 | − | − |
| Post-natal growth retardation | 10/11 | − | − |
| Psychomotor retardation | 19/19 | + | + |
| Hypotonia | 21/21 | + | + |
| Muscle atrophy | 13/13 | − | + |
| Dystonia | 19/21 | + | + |
| Hyperkinesia/athetoid movements | 12/13 | + | + |
| Neuropathy | 5/7 | + | + |
| Epilepsy/seizures/abnormal EEG | 3/16 | − | + |
| Deafness/sensorineural hearing deficit | 18/19 | + | + |
| Vision (ptosis, strabismus, ophalmoplegia) | 13/19 | − | + |
| Hyperhidrosis | 4/12 | − | − |
| Basal ganglia involvement (CT/MRI) | 15/17 | + | + |
| Plasma | |||
| Elevated lactate | 17/17 | − | + |
| Elevated MMA | 9/10 | NA | NA |
| Elevated acyl-carnitine C3 | 5/5 | NA | NA |
| Elevated acyl-carnitine C4-DC | 6/6 | NA | NA |
| Urine | |||
| Elevated MMA | 13/13 | + → −a | + |
| Elevated acyl-carnitine C3 | 1/4 | NA | NA |
| Elevated acyl-carnitine C4-DC | 5/5 | NA | NA |
| Elevated urine organic acids | |||
| Lactate | NA | − | + |
| 3-OH-isovalerate | 5/5 | NA | + |
| Methylmalonate | + | +b | + |
| Methylcitrate | 6/10 | NA | + |
| Succinate | + | NA | + |
| Multiple respiratory chain defect | +c | − | + |
| mtDNA relative amount | 15–57% | 65% | NA |
Abbreviations: CT, computed tomography; EEG, electroencephalography; MMA, methylmalonic acid; MRI, magnetic resonance imaging; NA, not available.
Symptoms characteristic of disease caused by mutations in SUCLA2 are in bold.
a
+ → − Elevated MMA in patient 1 normalized.
b
Marginal elevation.
c
All patients examined had a multiple respiratory chain defect.