G8299A

# **General Information**

| **Position** | **8299** | **Variant** | **m.8299G\>A** | **Locus** | **MT\-TK** | **RNA** | **tRNA Lys** |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Homoplasmy** | \- | **Heteroplasmy** | \+ | **mitoTIP** | 63\.80% | **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.8299G\>A** variant in MT\-TK has been reported in 1 pedigree. To date, 1 carrier has been reported. Reported mutation loads ranged from 0% to 50%, with a median of 25% overall; affected carriers showed mutation loads from 0% to 50%, with a median of 25%. In one affected carrier, the mutation was undetectable in blood (0%) but exceeded 20% in muscle (50%). The main clinical manifestations among affected carriers included pEO plus, cataract, dysarthria, external ophthalmoparesis, facial weakness, hearing loss, proximal tetraparesis, ptosis, and other features.

| **No.** | **Position** | **Variant** | **Family ID** | **Nationality** | **Diseases** | **Unaffected Maternal Relatives** | **Affected Maternal Relatives** | **Publication Year** | **PMID/Ref** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 8299 | m.8299G\>A | G8299A\-F1 | Germany | PEO; recurrent respiratory insufficiency | 0 | 0 | 2012 | [22326363](https://pubmed.ncbi.nlm.nih.gov/22326363/) | / |

# **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 | 8299 | m.8299G\>A | G8299A\-F1 | G8299A\-F1\-P1 | Uninf | M | Y | Y | D | 63 | 0 | 50% | / | / | PEO plus; recurrent respiratory insufficiency; dysarthria; ptosis; external ophthalmoparesis; facial weakness; proximal tetraparesis; hearing loss; cataract; retinal pigment changes | Muscle biopsy: ragged red fibers, 30% COX\-negative fibers; complex I/IV deficiency. G8299A 50% in muscle, absent from blood; mother and sister clinically healthy but muscle unavailable; inheritance unresolved. |

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