T8306C

# **General Information**

| **Position** | **8306** | **Variant** | **m.8306T\>C** | **Locus** | **MT\-TK** | **RNA** | **tRNA Lys** |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Homoplasmy** | \- | **Heteroplasmy** | \+ | **mitoTIP** | Pathogenic | **Pathogenicity** | Cfrm \[VUS\*] |

"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.8306T\>C** variant in MT\-TK has been reported in 1 pedigree. To date, 1 carrier has been reported. Reported mutation loads ranged from 1\.2% to 98%, with a median of 18\.8% overall; affected carriers showed mutation loads from 1\.2% to 98%, with a median of 18\.8%. In one affected carrier, a marked tissue\-specific difference was observed, with higher mutation loads in blood (5%), muscle (98%), urine (27%), bone marrow (17%), hair (30%), other tissue (97\.4%), other tissue (18\.8%), and cox\-positive single fibers (9\.2%) than in cox\-negative single fibers (1\.2%). The main clinical manifestations among affected carriers included severe adult\-onset myopathy, dysphagia, hypertrophic cardiomyopathy, insulin resistance, leukoencephalopathy, myoclonus, respiratory failure, and sensorineural deafness.

| **No.** | **Position** | **Variant** | **Family ID** | **Nationality** | **Diseases** | **Unaffected Maternal Relatives** | **Affected Maternal Relatives** | **Publication Year** | **PMID/Ref** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 8306 | m.8306T\>C | T8306C\-F1 | Italian | Adult\-onset mitochondrial myopathy; myoclonus; leukoencephalopathy; sensorineural deafness; hypertrophic cardiomyopathy; insulin resistance | 0 | 0 | 2012 | [22925535](https://pubmed.ncbi.nlm.nih.gov/22925535/) | / |

# **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 | 8306 | m.8306T\>C | T8306C\-F1 | T8306C\-F1\-P1 | De novo | M | Y | Y | A | 67 | 5% | 98% | 27% | 17% (BM); 30% (H); 97\.4\+/\-1\.2% (COX\-negative single fibers); 18\.8\+/\-9\.2% (COX\-positive single fibers) | Severe adult\-onset myopathy; myoclonus; leukoencephalopathy; sensorineural deafness; hypertrophic cardiomyopathy; insulin resistance; dysphagia; respiratory failure | Probable de novo; maternal transmission could not be excluded because mother was unavailable. |

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