T8777C

# **General Information**

| **Position** | **8777** | **Variant** | **m.8777T\>C** | **Locus** | **MT\-ATP6** | **Amino\-AcidChange** | **L84P** |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Homoplasmy** | \- | **Heteroplasmy** | \+ | **APOGEE2** | VUS\+ | **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.8777T\>C** variant in MT\-ATP6 has been reported in 2 pedigrees. To date, 2 carriers have been reported. Reported mutation loads ranged from 52% to 81%, with a median of 70% overall; affected carriers showed mutation loads from 52% to 81%, with a median of 70%. The main clinical manifestations among affected carriers included adult\-onset cerebellar ataxia, mild cognitive impairment, and severe optic atrophy.

| **No.** | **Position** | **Variant** | **Family ID** | **Nationality** | **Diseases** | **Unaffected Maternal Relatives** | **Affected Maternal Relatives** | **Publication Year** | **PMID/Ref** | **Note** |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 8777 | m.8777T\>C | T8777C\-F1 | Italy | Adult\-onset cerebellar ataxia with optic atrophy | 0 | 0 | 2024 | [38755691](https://pubmed.ncbi.nlm.nih.gov/38755691/) |  |
| 2 | 8777 | m.8777T\>C | T8777C\-F2 | Italy | Adult\-onset cerebellar ataxia with optic atrophy | 0 | 0 | 2024 | [38755691](https://pubmed.ncbi.nlm.nih.gov/38755691/) |  |

# **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 | 8777 | m.8777T\>C | T8777C\-F1 | T8777C\-F1\-P1 | Uninf | M | Y | Y | A | ND | / | 70% | / | / | Adult\-onset cerebellar ataxia; severe optic atrophy; mild cognitive impairment | Carrying G8879T |
| 2 | 8777 | m.8777T\>C | T8777C\-F2 | T8777C\-F2\-P1 | Uninf | F | Y | Y | A | ND | / | 81% | 52% | / | Adult\-onset cerebellar ataxia; severe optic atrophy; mild cognitive impairment |  |

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