G8342A

# **General Information**

| **Position** | **8342** | **Variant** | **m.8342G\>A** | **Locus** | **MT\-TK** | **RNA** | **tRNA Lys** |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Homoplasmy** | \- | **Heteroplasmy** | \+ | **mitoTIP** | 77\.20% | **Pathogenicity** | Reported \[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.8342G\>A** variant in MT\-TK has been reported in 1 pedigree. To date, 2 carriers have been reported. Reported mutation loads ranged from 0% to 80%, with a median of 0% overall; affected carriers showed mutation loads from 0% to 80%, with a median of 40%; unaffected carriers showed mutation loads from 0%, with a median of 0%. In one affected carrier, the mutation was undetectable in blood (0%) but exceeded 20% in muscle (80%). The main clinical manifestations among affected carriers included PEO, atopic eczema, fatigability, goiter, myoclonus, proximal weakness, ptosis, and tremor.

| **No.** | **Position** | **Variant** | **Family ID** | **Nationality** | **Diseases** | **Unaffected Maternal Relatives** | **Affected Maternal Relatives** | **Publication Year** | **PMID/Ref** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 8342 | m.8342G\>A | [G8342A\-F1](https://mitofam.com/doc/2202/) | Italy | Progressive external ophthalmoplegia; myoclonus | 1 | 0 | 1999 | [10220860](https://pubmed.ncbi.nlm.nih.gov/10220860/) | / |

# **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 | 8342 | m.8342G\>A | G8342A\-F1 | G8342A\-F1\-III1 | Fam | F | N | N | A | 10 | 0 | / | / | / | Healthy | Tested negative in lymphocyte DNA; eligible negative\-tested child of a target\-positive mother. |
| 2 | 8342 | m.8342G\>A | G8342A\-F1 | G8342A\-F1\-II1 | De novo | F | Y | Y | A | 39 | 0 | 80% | / | / | PEO; ptosis; proximal weakness; fatigability; myoclonus; tremor; atopic eczema; goiter | Mutation absent in proband lymphocyte DNA but about 80% in muscle. |

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