T8316C

# **General Information**

| **Position** | **8316** | **Variant** | **m.8316T\>C** | **Locus** | **MT\-TK** | **RNA** | **tRNA Lys** |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Homoplasmy** | \- | **Heteroplasmy** | \+ | **mitoTIP** | 80\.20% | **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.8316T\>C** variant in MT\-TK has been reported in 1 pedigree. To date, 5 carriers have been reported. Homoplasmy was reported in 1/5 carriers (20%), and 1/5 carriers (20%) were affected. In one affected carrier, a marked tissue\-specific difference was observed, with higher mutation loads in muscle (homoplasmy) than in blood (45%). The main clinical manifestations among affected carriers included MELAS, exercise intolerance, learning disability, mild dilated cardiomyopathy, myoclonus, ophthalmoparesis, respiratory insufficiency, stroke\-like episode, and other features.

| **No.** | **Position** | **Variant** | **Family ID** | **Nationality** | **Diseases** | **Unaffected Maternal Relatives** | **Affected Maternal Relatives** | **Publication Year** | **PMID/Ref** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 8316 | m.8316T\>C | [T8316C\-F1](https://mitofam.com/doc/2214/) | Spain | MELAS; mitochondrial myopathy; lactic acidosis; stroke\-like episodes | 4 | 0 | 2000 | [10996780](https://pubmed.ncbi.nlm.nih.gov/10996780/) | / |

# **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 | 8316 | m.8316T\>C | T8316C\-F1 | T8316C\-F1\-III1 | Fam | F | N | N | A | ND | 14% | / | / | / | Healthy | Original label III\-1\. |
| 2 | 8316 | m.8316T\>C | T8316C\-F1 | T8316C\-F1\-III2 | Fam | M | N | N | A | ND | 7% | / | / | / | Healthy | Original label III\-2\. |
| 3 | 8316 | m.8316T\>C | T8316C\-F1 | T8316C\-F1\-III3 | Fam | M | N | N | A | ND | 6% | / | / | / | Healthy | Original label III\-3\. |
| 4 | 8316 | m.8316T\>C | T8316C\-F1 | T8316C\-F1\-IV2 | Fam | F | Y | Y | A | 14 | 45% | Homo | / | / | MELAS; learning disability; exercise intolerance; ophthalmoparesis; weakness; stroke\-like episode; myoclonus; respiratory insufficiency; mild dilated cardiomyopathy | Proposita IV\-2; muscle homoplasmic, blood 45%. |
| 5 | 8316 | m.8316T\>C | T8316C\-F1 | T8316C\-F1\-IV1 | Fam | M | N | N | A | ND | 0 | / | / | / | Healthy | Original label IV\-1; mutation not detected in blood. |

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