T14487C

# **General Information**

| **Position** | **14487** | **Variant** | **m.14487T\>C** | **Locus** | **MT\-ND6** | **Amino\-AcidChange** | **M63V** |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Homoplasmy** | \- | **Heteroplasmy** | \+ | **APOGEE2** | Pathogenic | **Pathogenicity** | Cfrm \[P] |

"Pathogenicity" status is derived from published literature or predictions from bioinformatics tools. Researchers and clinicians are cautioned that additional data and/or analysis may still be necessary to confirm the pathological significance of these variants. For more information, please see [Mitofam Info](https://mitofam.com/doc/385/).

# **Pedigree Information**

The **m.14487T\>C** variant in MT\-ND6 has been reported in 34 pedigrees. To date, 63 carriers have been reported. Homoplasmy was reported in 3/63 carriers (4\.8%), and 43/63 carriers (68\.3%) were affected. In one unaffected carrier, a marked tissue\-specific difference was observed, with higher mutation loads in urine (82\.7%) and hair (82\.4%) than in blood (37\.5%). In one unaffected carrier, a marked tissue\-specific difference was observed, with higher mutation loads in urine (56\.4%) and bone marrow (54\.3%) than in hair (22\.3%). Similar tissue\-specific differences were observed in 7 additional carriers. The main clinical manifestations among affected carriers included leigh syndrome, hypotonia, optic atrophy, seizures, mitochondrial Leigh syndrome, ataxia, basal ganglia, complex I deficiency, and other features.

| **No.** | **Position** | **Variant** | **Family ID** | **Nationality** | **Diseases** | **Unaffected Maternal Relatives** | **Affected Maternal Relatives** | **Publication Year** | **PMID/Ref** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 14487 | m.14487T\>C | T14487C\-F1 | Spain | bilateral striatal necrosis and dystonia | 1 | 0 | 2003 | [14520668](https://pubmed.ncbi.nlm.nih.gov/14520668/) |  |
| 2 | 14487 | m.14487T\>C | T14487C\-F2 | Spain | bilateral striatal necrosis and dystonia | 0 | 0 | 2003 | [14520668](https://pubmed.ncbi.nlm.nih.gov/14520668/) |  |
| 3 | 14487 | m.14487T\>C | T14487C\-F3 | Netherlands | Leigh syndrome | 1 | 0 | 2003 | [14595656](https://pubmed.ncbi.nlm.nih.gov/14595656/) |  |
| 4 | 14487 | m.14487T\>C | T14487C\-F4 | France | Leigh or Leigh\-like encephalopathy with isolated complex I deficiency | 0 | 4 | 2003 | [14684687](https://pubmed.ncbi.nlm.nih.gov/14684687/) |  |
| 5 | 14487 | m.14487T\>C | T14487C\-F5 | Italy | Leigh syndrome | 0 | 0 | 2004 | [15576045](https://pubmed.ncbi.nlm.nih.gov/15576045/) |  |
| 6 | 14487 | m.14487T\>C | T14487C\-F6 | Spain | Bilateral striatal lesion syndrome; progressive dystonia; Leigh\-like complex I deficiency | 0 | 0 | 2004 | [15625630](https://pubmed.ncbi.nlm.nih.gov/15625630/) |  |
| 7 | 14487 | m.14487T\>C | T14487C\-F7 | Sweden | Leigh syndrome; complex I deficiency | 0 | 0 | 2005 | [16044424](https://pubmed.ncbi.nlm.nih.gov/16044424/) |  |
| 8 | 14487 | m.14487T\>C | [T14487C\-F8](https://mitofam.com/doc/2151/) | Italy | Leigh syndrome | 0 | 0 | 2007 | [17535832](https://pubmed.ncbi.nlm.nih.gov/17535832/) |  |
| 9 | 14487 | m.14487T\>C | T14487C\-F9 | Italy | Optic atrophy and ataxia | 0 | 0 | 2007 | [17535832](https://pubmed.ncbi.nlm.nih.gov/17535832/) |  |
| 10 | 14487 | m.14487T\>C | [T14487C\-F10](https://mitofam.com/doc/2152/) | Canada | Leigh syndrome | 5 | 2 | 2008 | [19062322](https://pubmed.ncbi.nlm.nih.gov/19062322/) | Carrying T12297C; Fig. 1 |
| 11 | 14487 | m.14487T\>C | T14487C\-F11 | Sweden | Leigh syndrome | 0 | 0 | 2009 | [19103152](https://pubmed.ncbi.nlm.nih.gov/19103152/) |  |
| 12 | 14487 | m.14487T\>C | T14487C\-F12 | Sweden | Leigh syndrome | 0 | 1 | 2009 | [19103152](https://pubmed.ncbi.nlm.nih.gov/19103152/) |  |
| 13 | 14487 | m.14487T\>C | [T14487C\-F13](https://mitofam.com/doc/2153/) | Belgium | Leigh syndrome and progressive myoclonic epilepsy | 2 | 7 | 2010 | [20019223](https://pubmed.ncbi.nlm.nih.gov/20019223/) |  |
| 14 | 14487 | m.14487T\>C | T14487C\-F14 | Israel | Leigh syndrome | 0 | 0 | 2011 | [21196529](https://pubmed.ncbi.nlm.nih.gov/21196529/) | Carrying C15674T and A15326G |
| 15 | 14487 | m.14487T\>C | T14487C\-F15 | Australia | Leigh syndrome | 0 | 0 | 2011 | [21364701](https://pubmed.ncbi.nlm.nih.gov/21364701/) |  |
| 16 | 14487 | m.14487T\>C | T14487C\-F16 | Australia | Leigh syndrome | ND | ND | 2011 | [21364701](https://pubmed.ncbi.nlm.nih.gov/21364701/) |  |
| 17 | 14487 | m.14487T\>C | T14487C\-F17 | Australia | Mitochondrial encephalomyopathy | ND | ND | 2011 | [21364701](https://pubmed.ncbi.nlm.nih.gov/21364701/) |  |
| 18 | 14487 | m.14487T\>C | T14487C\-F18 | Canada | Severe infantile Leigh syndrome | 0 | 0 | 2013 | [23813926](https://pubmed.ncbi.nlm.nih.gov/23813926/) |  |
| 19 | 14487 | m.14487T\>C | T14487C\-F19 | France | Leigh syndrome | 0 | 0 | 2013 | [23847141](https://pubmed.ncbi.nlm.nih.gov/23847141/) |  |
| 20 | 14487 | m.14487T\>C | T14487C\-F20 | France | Leigh syndrome | 0 | 0 | 2013 | [23847141](https://pubmed.ncbi.nlm.nih.gov/23847141/) |  |
| 21 | 14487 | m.14487T\>C | T14487C\-F21 | France | Leigh syndrome | 0 | 0 | 2013 | [23847141](https://pubmed.ncbi.nlm.nih.gov/23847141/) |  |
| 22 | 14487 | m.14487T\>C | T14487C\-F22 | United Kingdom | optic atrophy; ptosis; encephalomyopathy; seizures | 1 | 1 | 2013 | [24126373](https://pubmed.ncbi.nlm.nih.gov/24126373/) |  |
| 23 | 14487 | m.14487T\>C | T14487C\-F23 | Germany | LHON | 1 | 0 | 2015 | [26530508](https://pubmed.ncbi.nlm.nih.gov/26530508/) |  |
| 24 | 14487 | m.14487T\>C | [T14487C\-F24](https://mitofam.com/doc/2154/) | Italy | Leigh syndrome | 2 | 1 | 2017 | [28122886](https://pubmed.ncbi.nlm.nih.gov/28122886/) |  |
| 25 | 14487 | m.14487T\>C | T14487C\-F25 | Japan | Leigh syndrome | 0 | 0 | 2017 | [28429146](https://pubmed.ncbi.nlm.nih.gov/28429146/) |  |
| 26 | 14487 | m.14487T\>C | T14487C\-F26 | Japan | Leigh syndrome | 0 | 0 | 2017 | [28429146](https://pubmed.ncbi.nlm.nih.gov/28429146/) |  |
| 27 | 14487 | m.14487T\>C | T14487C\-F27 | China | Late\-onset Leigh syndrome | 0 | 0 | 2018 | [30128709](https://pubmed.ncbi.nlm.nih.gov/30128709/) |  |
| 28 | 14487 | m.14487T\>C | T14487C\-F28 | China | Mitochondrial Leigh syndrome | 0 | 0 | 2020 | [32162843](https://pubmed.ncbi.nlm.nih.gov/32162843/) |  |
| 29 | 14487 | m.14487T\>C | T14487C\-F29 | China | Mitochondrial Leigh syndrome | 0 | 0 | 2020 | [32162843](https://pubmed.ncbi.nlm.nih.gov/32162843/) |  |
| 30 | 14487 | m.14487T\>C | T14487C\-F30 | China | Mitochondrial Leigh syndrome | 0 | 0 | 2020 | [32162843](https://pubmed.ncbi.nlm.nih.gov/32162843/) |  |
| 31 | 14487 | m.14487T\>C | T14487C\-F31 | United Kingdom | Progressive myoclonic epilepsy; bilateral optic neuropathy; mitochondrial disease | 0 | 2 | 2021 | [34223155](https://pubmed.ncbi.nlm.nih.gov/34223155/) |  |
| 32 | 14487 | m.14487T\>C | T14487C\-F32 | Germany | isolated complex I deficiency | 0 | 0 | 2022 | [35715829](https://pubmed.ncbi.nlm.nih.gov/35715829/) |  |
| 33 | 14487 | m.14487T\>C | T14487C\-F33 | Italy | Leigh syndrome | 0 | 0 | 2012 | [23010433](https://pubmed.ncbi.nlm.nih.gov/23010433/) |  |
| 34 | 14487 | m.14487T\>C | T14487C\-F34 | China | Leigh disease | 0 | 0 | 2016 | [27338358](https://pubmed.ncbi.nlm.nih.gov/27338358/) |  |

# **Carrier Information**

| **No.** | **Position** | **Variant** | **Family ID** | **Carrier ID** | **Type (Fam/De novo/Uninf)** | **Gender (F/M)** | **Proband (Y/N)** | **Affected (Y/N)** | **Die/Alive(D/A)** | **Age** | **Blood Mutant Level** | **Muscle Mutant level** | **Urine Mutant level** | **Other Mutant level** | **Clinical Features** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 14487 | m.14487T\>C | T14487C\-F1 | T14487C\-F1\-P1 | Fam | M | Y | Y | ND | 15 | 67% | 93% | / | / | Progressive generalized dystonia with BSN; onset age 4; severe dysarthria; moderate mental retardation |  |
| 2 | 14487 | m.14487T\>C | T14487C\-F1 | T14487C\-F1\-P2 | Fam | F | N | N | ND | ND | 26% | / | / | / | No BSN/dystonia phenotype reported | Original label P1mother |
| 3 | 14487 | m.14487T\>C | T14487C\-F2 | T14487C\-F2\-P1 | Uninf | M | Y | Y | ND | 15 | 94% | / | / | / | Progressive dystonia with BSN; onset age 6; severe dystonic tetraplegia | Original label P2 |
| 4 | 14487 | m.14487T\>C | T14487C\-F3 | T14487C\-F3\-P1 | Fam | M | Y | Y | D | 4 months | / | 65% | / | 65% (Liver); 86% (F) | Leigh syndrome; tonic\-clonic seizure; cardiorespiratory arrest; motor retardation; hypotonia; deafness; pyramidal/extrapyramidal signs; oculomotor palsies; strabismus; stupor; recurrent apnea; optic atrophy; lactic acidemia; basal ganglia lesions; fatal |  |
| 5 | 14487 | m.14487T\>C | T14487C\-F3 | T14487C\-F3\-P2 | Fam | F | N | N | ND | ND | 24% | / | / | / | Healthy |  |
| 6 | 14487 | m.14487T\>C | T14487C\-F4 | T14487C\-F4\-P1 | Fam | M | Y | Y | A | 32 months | / | 80% | / | / | Acute ataxia, drowsiness, vomiting, MRI basal\-ganglia lesions suggestive of Leigh encephalopathy, second regression with dystonia and dysarthria, wheelchair bound with severe spasticity | Original label P3 |
| 7 | 14487 | m.14487T\>C | T14487C\-F4 | T14487C\-F4\-P2 | Fam | F | N | ND | ND | ND | \<15% | / | / | / | Phenotype not reported | Original label P3mother |
| 8 | 14487 | m.14487T\>C | T14487C\-F5 | T14487C\-F5\-P1 | Uninf | ND | Y | Y | ND | ND | \>95% | \>95% | / | / | Leigh syndrome; lactic acidosis; increased CSF lactate; complex I activity 25 percent in muscle and normal in fibroblasts | Original label P6 |
| 9 | 14487 | m.14487T\>C | T14487C\-F6 | T14487C\-F6\-P1 | Uninf | M | Y | Y | A | 18y | / | / | / | / | Bilateral striatal lesions; progressive dystonia; cognitive impairment; complex I deficiency; dysarthria; dysphagia |  |
| 10 | 14487 | m.14487T\>C | T14487C\-F7 | T14487C\-F7\-P1 | Fam | F | Y | Y | A | 9 y | / | 95% | / | 76% (F) | Delayed psychomotor development; walking difficulty; muscle weakness; ataxia; vomiting; choreoathetosis; epilepsy; severe spasticity; basal ganglia lesions | Original label P3 |
| 11 | 14487 | m.14487T\>C | T14487C\-F7 | T14487C\-F7\-P2 | Fam | F | N | ND | ND | ND | 2% | / | / | / | Phenotype not reported |  |
| 12 | 14487 | m.14487T\>C | T14487C\-F8 | T14487C\-F8\-II1 | Fam | M | Y | Y | A | 10 mo | / | \>95% | / | 85% (F) | Leigh syndrome; developmental delay/regression; hypotonia; eye movement incoordination; drooling; dysphagia; focal epileptic fits; lactic acidosis; basal ganglia/thalamic/brainstem lesions; dilating cardiomyopathy; optic disk pallor | Original label P3 |
| 13 | 14487 | m.14487T\>C | T14487C\-F8 | T14487C\-F8\-I2 | Fam | F | N | ND | ND | ND | 50% | / | / | / | No clinical features reported |  |
| 14 | 14487 | m.14487T\>C | T14487C\-F9 | T14487C\-F9\-P1 | Uninf | ND | Y | Y | A | 20 yr | 50% | 50% | / | / | Optic atrophy; cerebellar ataxia; dysarthria; lower\-limb hyperreflexia; delayed/disorganized visual and auditory evoked responses; basal ganglia/substantia nigra/periaqueductal gray lesions | Original label P5 |
| 15 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-IV5 | Fam | F | Y | Y | D | 10 months | / | 99\.8% | / | / | Central hypotonia, developmental delay, high blood lactate, basal ganglia and brainstem MRI lesions, progressive hypotonia/spasticity/vision loss, respiratory failure | Original label IV\-5 |
| 16 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-IV4 | Fam | M | N | N | A | 5 | / | / | 90\.8% | 94\.5% (H); 92\.0% (BM) | Healthy | Original label IV\-4 |
| 17 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-II5 | Fam | F | N | N | A | 68 | 37\.5% | / | 82\.7% | 82\.4% (H); 62\.8% (BM) | Healthy | Original label II\-5 |
| 18 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-III3 | Fam | F | N | N | A | 38 | 43\.2% | / | 69\.4% | 73\.1% (H); 67\.5% (BM) | No significant cardiomyopathy signs reported; no Leigh phenotype reported | Original label III\-3 |
| 19 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-III6 | Fam | F | N | N | A | 35 | 40\.2% | / | 56\.4% | 22\.3% (H); 54\.3% (BM) | No significant cardiomyopathy signs reported; no Leigh phenotype reported | Original label III\-6 |
| 20 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-IV8 | Fam | F | N | N | A | 3 | / | / | 16\.9% | 13\.8% (H); 15\.6% (BM) | No Leigh phenotype reported in text | Original label IV\-8 |
| 21 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-III7 | Fam | F | N | Y | D | 13 months | / | / | / | / | Nystagmus, lethargy, developmental arrest, seizures, progressive hypotonia, truncal ataxia, CT brain lesions, increased urine lactate, Leigh syndrome |  |
| 22 | 14487 | m.14487T\>C | T14487C\-F10 | T14487C\-F10\-III5 | Fam | M | N | Y | D | 15 years | / | / | / | / | Developmental regression and hypotonia at 10 months, seizures, lethargy, vision loss, profound developmental delay, Leigh syndrome |  |
| 23 | 14487 | m.14487T\>C | T14487C\-F11 | T14487C\-F11\-P1 | Uninf | F | Y | Y | A | 16 y | / | High; exact value in Ref. \[9] | / | / | Leigh syndrome; onset at birth; severe slightly progressive handicap; developmental retardation, hypotonia, spasticity/hypertonia, ataxia, dystonia/dyskinesia, seizures; no optic atrophy reported | Original label P11 |
| 24 | 14487 | m.14487T\>C | T14487C\-F12 | T14487C\-F12\-P1 | Fam | M | Y | Y | D | 5 mo | / | Homo | / | / | Leigh syndrome; onset 5 mo; sudden irritability, hypertonus and hypoventilation; rapid deterioration and death within three weeks after admission | Original label P14 |
| 25 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-II3 | Fam | ND | N | Y | A | 72 years | 8% | / | / | / | Migraine with aura and diabetes mellitus type 2 | Original label II\-3 |
| 26 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-III4 | Fam | ND | N | Y | A | 56 years | 35% | / | / | / | Subclinical LHON | Original label III\-4 |
| 27 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-III6 | Fam | ND | N | Y | A | 48 years | 19% | / | / | / | Migraine with aura and sensorineural hearing loss | Original label III\-6 |
| 28 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-IV2 | Fam | ND | N | N | A | 34 years | 32% | / | / | / | Healthy | Original label IV\-2 |
| 29 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-IV3 | Fam | M | Y | Y | A | 32 years | 36% | 97% | / | / | PME with LHON and progressive hypokinetic\-rigid syndrome | Original label IV\-3 |
| 30 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-IV4 | Fam | ND | Y | Y | D | 2 years | 99% | / | / | 100% (F) | Leigh syndrome with structural cardiopathy | Original label IV\-4 |
| 31 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-IV5 | Fam | M | Y | Y | A | 28 years | 52% | 99% | / | / | PME with dysarthria SNHL hemiparesis epilepsy dysphagia and cognitive deterioration | Original label IV\-5 |
| 32 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-V1 | Fam | ND | Y | Y | D | 3\.5 months | 100% | 100% | / | / | Leigh syndrome with mitochondrial hypertrophic cardiomyopathy | Original label V\-1 |
| 33 | 14487 | m.14487T\>C | T14487C\-F13 | T14487C\-F13\-V2 | Fam | ND | N | N | A | 19 months | 83% | / | / | / | Healthy | Original label V\-2 |
| 34 | 14487 | m.14487T\>C | T14487C\-F14 | T14487C\-F14\-P1 | De novo | F | Y | Y | A | 24 years | 25% | 85% | / | / | Juvenile\-onset Leigh syndrome; optic atrophy; ataxia; dystonia; epilepsy |  |
| 35 | 14487 | m.14487T\>C | T14487C\-F15 | T14487C\-F15\-P1 | Uninf | ND | Y | Y | ND | ND | / | \>98% | / | / | Leigh syndrome |  |
| 36 | 14487 | m.14487T\>C | T14487C\-F16 | T14487C\-F16\-P1 | Fam | ND | Y | Y | ND | ND | / | / | / | \>98% (F) | Leigh syndrome |  |
| 37 | 14487 | m.14487T\>C | T14487C\-F16 | T14487C\-F16\-P2 | Fam | F | N | ND | ND | ND | / | / | 20% | / | ND |  |
| 38 | 14487 | m.14487T\>C | T14487C\-F17 | T14487C\-F17\-P1 | Fam | M | Y | Y | ND | 12\.5 years | / | \>98% | / | / | Deteriorating vision; pale optic discs; migraines; school performance deterioration; bilateral hearing loss; obsessive compulsive disorder |  |
| 39 | 14487 | m.14487T\>C | T14487C\-F17 | T14487C\-F17\-P2 | Fam | F | N | ND | ND | ND | 24% | / | / | / | ND |  |
| 40 | 14487 | m.14487T\>C | T14487C\-F18 | T14487C\-F18\-P1 | De novo | M | Y | Y | D | 6\.5 mo | / | 99\.4% | / | / | Severe infantile Leigh syndrome; delayed gross motor development; respiratory failure; basal ganglia/thalamus/brain stem MRI changes; nystagmus, hypotonia, brisk reflexes; complex I deficiency | Original label P1 |
| 41 | 14487 | m.14487T\>C | T14487C\-F19 | T14487C\-F19\-P1 | Uninf | M | Y | Y | ND | 1\-16 onset | / | / | / | Homo (ND) | CNS PMR stroke\-like pyramidal signs; ptosis; Leigh; increased CSF lactate; decreased CI in muscle |  |
| 42 | 14487 | m.14487T\>C | T14487C\-F20 | T14487C\-F20\-P1 | Uninf | F | Y | Y | ND | 1\-16 onset | / | / | / | Heteroplasmic (ND) | CNS PMR stroke\-like; PEO; postnatal growth failure; Leigh; increased CSF lactate; RC normal in muscle |  |
| 43 | 14487 | m.14487T\>C | T14487C\-F21 | T14487C\-F21\-P1 | Uninf | M | Y | Y | ND | 1\-16 onset | / | / | / | Heteroplasmic (ND) | CNS regression dystonia pyramidal signs; Leigh and stroke\-like MRI; increased blood lactate; RC normal in muscle/fibroblast |  |
| 44 | 14487 | m.14487T\>C | T14487C\-F22 | T14487C\-F22\-P1 | Fam | M | Y | Y | A | 23 | 15% | 84% | 75% | 58% (BM); 86% (H) | bilateral optic atrophy; ptosis; fluctuating leukoencephalopathy; myoclonic epilepsy | Original label Twin1 |
| 45 | 14487 | m.14487T\>C | T14487C\-F22 | T14487C\-F22\-P2 | Fam | M | N | Y | A | 26 | 17% | / | 71% | 57% (BM); 74% (H) | bilateral optic atrophy; ptosis; seizures; right arm jerks | Original label Twin2 |
| 46 | 14487 | m.14487T\>C | T14487C\-F22 | T14487C\-F22\-P3 | Fam | F | N | N | A | ND | 5% | / | 25% | 30% (BM); 34% (H) | Healthy |  |
| 47 | 14487 | m.14487T\>C | T14487C\-F23 | T14487C\-F23\-P1 | Fam | M | Y | Y | A | 16\.5 years | 80\-90% | / | / | / | Bilateral optic neuropathy/LHON; blurred vision; bilateral central scotomata; temporal optic atrophy; no other neurologic symptoms reported; vision recovered after idebenone |  |
| 48 | 14487 | m.14487T\>C | T14487C\-F23 | T14487C\-F23\-P2 | Fam | F | N | N | A | ND | 30% | / | 50% | / | Healthy |  |
| 49 | 14487 | m.14487T\>C | T14487C\-F24 | T14487C\-F24\-IV1 | Fam | M | N | Y | D | 8 y | 99% | \>95% | / | 97% (F) | Leigh syndrome; growth delay from 6 mo; psychomotor stagnation; hypotonia; typical brain MRI lesions; feeding difficulties; recurrent aspiration pneumonias; tracheostomy |  |
| 50 | 14487 | m.14487T\>C | T14487C\-F24 | T14487C\-F24\-III1 | Fam | F | Y | N | A | 39 y | 32% | 55% | 65% | / | Healthy |  |
| 51 | 14487 | m.14487T\>C | T14487C\-F24 | T14487C\-F24\-II1 | Fam | F | N | ND | ND | ND | 5% | / | 10% | / | Phenotype not reported |  |
| 52 | 14487 | m.14487T\>C | T14487C\-F24 | T14487C\-F24\-III2 | Fam | F | N | ND | ND | ND | \<10% | \<10% | 10% | / | Phenotype not reported |  |
| 53 | 14487 | m.14487T\>C | T14487C\-F24 | T14487C\-F24\-IV2 | Fam | M | N | N | A | 7 mo | 5% | / | / | / | Healthy |  |
| 54 | 14487 | m.14487T\>C | T14487C\-F25 | T14487C\-F25\-P1 | Uninf | ND | Y | Y | ND | ND | 99% | / | / | / | Leigh syndrome; isolated complex I deficiency | Original label Pt224 |
| 55 | 14487 | m.14487T\>C | T14487C\-F26 | T14487C\-F26\-P1 | Uninf | ND | Y | Y | ND | ND | Nearly 100% | / | / | / | Leigh syndrome; enzyme assay not significant | Original label Pt1063 |
| 56 | 14487 | m.14487T\>C | T14487C\-F27 | T14487C\-F27\-P1 | Uninf | F | Y | Y | ND | 2\.5 | 99% | / | / | / | Mental retardation; extrapyramidal signs; bulbar palsy; developmental delay; failure to thrive | Original label Case10 |
| 57 | 14487 | m.14487T\>C | T14487C\-F28 | T14487C\-F28\-P1 | Uninf | ND | Y | Y | ND | ND | 85% | / | / | / | Mitochondrial Leigh syndrome | Original label P1 |
| 58 | 14487 | m.14487T\>C | T14487C\-F29 | T14487C\-F29\-P1 | Uninf | ND | Y | Y | ND | ND | 95% | / | / | Homo (BM) | Mitochondrial Leigh syndrome | Original label P2 |
| 59 | 14487 | m.14487T\>C | T14487C\-F30 | T14487C\-F30\-P1 | Uninf | ND | Y | Y | ND | ND | 100% | / | / | / | Mitochondrial Leigh syndrome | Original label P3 |
| 60 | 14487 | m.14487T\>C | T14487C\-F31 | T14487C\-F31\-P1 | Fam | M | Y | Y | A | 43 | / | 98% | / | / | Adult\-onset drug\-resistant epilepsy; cortical myoclonus; bilateral visual loss/optic atrophy; axonal neuropathy; stroke\-like MRI lesions; dysphagia |  |
| 61 | 14487 | m.14487T\>C | T14487C\-F32 | T14487C\-F32\-P1 | Uninf | ND | ND | Y | ND | ND | / | / | / | Positive (F) | complex I deficiency |  |
| 62 | 14487 | m.14487T\>C | T14487C\-F33 | T14487C\-F33\-P1 | Uninf | M | Y | Y | A | 7 y | / | / | / | / | Leigh syndrome; MRI\-confirmed necrotizing encephalopathy; NPMDS baseline 45 | EPI\-743 |
| 63 | 14487 | m.14487T\>C | T14487C\-F34 | T14487C\-F34\-P1 | Uninf | M | Y | Y | A | 4 y | / | / | / | 70% (ND) | Leigh disease | Original label Patient 2 |

For abbreviations and other usage instructions, please see [Mitofam Info](https://mitofam.com/doc/385/).