Table 2.
Clinical disorders that are caused by mutations in mitochondrial DNA
| Mitochondrial DNA Disorder | Clinical phenotype | mtDNA genotype | Gene | Status | Inheritance | Reference |
|---|---|---|---|---|---|---|
| Kearns–Sayre syndrome | Progressive myopathy, ophthalmoplegia, cardiomyopathy | A single, large-scale deletion | Several deleted genes | Heteroplasmic | Usually sporadic | 61,158 |
| CPEO | Ophthalmoplegia | A single, large-scale deletion | Several deleted genes | Heteroplasmic | Usually sporadic | 61, 64 |
| Pearson syndrome | Pancytopoenia, lactic acidosis | A single, large-scale deletion | Several deleted genes | Heteroplasmic | Usually sporadic | 65 |
| MELAS | Myopathy, encephalopathy lactic acidosis, stroke-like episodes | 3243A>G; 3271T>C | TRNL1 | Heteroplasmic | Maternal | 159 |
| Individual mutations | ND1 and ND5 | Heteroplasmic | Maternal | 160, 161 | ||
| MERRF | Myoclonic epilepsy, myopathy | 8344A>G; 8356T>C | TRNK | Heteroplasmic | Maternal | 162 |
| NARP | Neuropathy, ataxia, retinitis pigmentosa | 8993T>G | ATP6 | Heteroplasmic | Maternal | 163 |
| MILS | Progressive brain-stem disorder | 8993T>C | ATP6 | Heteroplasmic | Maternal | 67 |
| MIDD | Diabetes, deafness | 3243A>G | TRNL1 | Heteroplasmic | Maternal | 164 |
| LHON | Optic neuropathy | 3460G>A | ND1 | Hetero- or homoplasmic | Maternal | 165 |
| 11778G>A | ND4 | Hetero- or homoplasmic | Maternal | 62 | ||
| 14484T>C | ND6 | Hetero- or homoplasmic | Maternal | 166 | ||
| Myopathy and diabetes | Myopathy, weakness, diabetes | 14709T>C | TRNE | Hetero- or homoplasmic | Maternal | 167,168 |
| Sensorineural hearing loss | Deafness | 1555A>G | RNR1 | Homoplasmic | Maternal | 55 |
| Individual mutations | TRNS1 | Hetero- or homoplasmic | Maternal | 169,170 | ||
| Exercise intolerance | Fatigue, muscle weakness | Individual mutations | CYB | Heteroplasmic | Sporadic | 68 |
| Fatal, infantile encephalopathy; Leigh/Leigh-like syndrome | Encephalopathy, lactic acidosis | 10158T>C; 10191T>C | ND3 | Heteroplasmic | Sporadic | 66 |
ATP6, ATPase 6; CPEO, chronic progressive external ophthalmoplegia; CYB, cytochrome b; LHON, Leber hereditary optic neuropathy; MELAS, mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes; MERRF, myoclonic epilepsy and ragged-red fibres; MIDD, maternally-inherited diabetes and deafness; MILS, maternally-inherited Leigh syndrome; ND1,3–6, NADH dehydrogenase subunits 1,3–6; NARP, neurogenic weakness, ataxia and retinitis pigmentosa; RNR1, 12S ribosomal RNA; TRNE,TRNK,TRNL1,TRNS1, mitochondrial tRNAs.