T4274C

# **General Information**

| **Position** | **4274** | **Variant** | **m.4274T\>C** | **Locus** | **MT\-TI** | **RNA** | **tRNA Ile** |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Homoplasmy** | \- | **Heteroplasmy** | \+ | **mitoTIP** | 85\.50% | **Pathogenicity** | Reported |

"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.4274T\>C** variant in MT\-TI has been reported in 2 pedigrees. To date, 2 carriers have been reported. Reported mutation loads ranged from 37% to 81%, with a median of 47% overall; affected carriers showed mutation loads from 37% to 81%, with a median of 47%. The main clinical manifestations among affected carriers included bilateral median nerve compression, CPEO, active denervation, cardiac arrhythmia, diabetes, diminished reflexes, dysarthria, dysphonia, and other features.

| **No.** | **Position** | **Variant** | **Family ID** | **Nationality** | **Diseases** | **Unaffected Maternal Relatives** | **Affected Maternal Relatives** | **Publication Year** | **PMID/Ref** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 4274 | m.4274T\>C | T4274C\-F1 | UK | CPEO | NA | NA | 2006 | [16358336](https://pubmed.ncbi.nlm.nih.gov/16358336/) |  |
| 2 | 4274 | m.4274T\>C | T4274C\-F2 | UK | Motor neuron disease, cardiomyopathy,diabetes | NA | NA | 2006 | [16358336](https://pubmed.ncbi.nlm.nih.gov/16358336/) |  |

# **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 | 4274 | m.4274T\>C | T4274C\-F1 | T4274C\-F1\-P1 | Uninf | F | Y | Y | A | 30 | / | 81% | / | / | CPEO |  |
| 2 | 4274 | m.4274T\>C | T4274C\-F2 | T4274C\-F2\-P1 | Uninf | M | Y | Y | D | 73 | / | / | / | 45%(motor cortex); 37%(pons); 47%(thoracic anterior horn); 48%(anterior horn cervical cord) | Bilateral median nerve compression, progressive limb weakness, generalized muscle atrophy, dysphonia, dysarthria, active denervation, diminished reflexes, no fasciculations, intact sensation, diabetes, myocardial infarction, cardiac arrhythmia |  |

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