MERRF syndrome
Findings
No curated finding names MERRF syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
A rare mitochondrial oxidative phosphorylation disorder characterized by myoclonic seizures, ataxia, generalized epilepsy, muscle weakness and ragged red fibers in the muscle biopsy.
Definition from the Mondo Disease Ontology (MONDO:0010790), read 2026-09-29. CC BY 4.0.
Features
11 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Abnormality of movementHPOHP:0100022
- Very frequent (80% to 99% of cases)
- AtaxiaHPOHP:0001251
- Very frequent (80% to 99% of cases)
- EMG abnormalityHPOHP:0003457
- Very frequent (80% to 99% of cases)
- Generalized myoclonic seizureHPOHP:0002123
- Very frequent (80% to 99% of cases)
- MyopathyHPOHP:0003198
- Very frequent (80% to 99% of cases)
- Ragged-red muscle fibersHPOHP:0003200
- Very frequent (80% to 99% of cases)
- Sensorineural hearing impairmentHPOHP:0000407
- Very frequent (80% to 99% of cases)
- Cognitive impairmentHPOHP:0100543
- Frequent (30% to 79% of cases)
- Multiple lipomasHPOHP:0001012
- Frequent (30% to 79% of cases)
- Optic atrophyHPOHP:0000648
- Frequent (30% to 79% of cases)
- Short statureHPOHP:0004322
- Frequent (30% to 79% of cases)
Genes
7 genes
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- HGNC:7494HGNC:7494
- Definitive · G2P · Mitochondrial · 2015
- Supportive · Orphanet · Mitochondrial · 2025
- HGNC:7481HGNC:7481
- Supportive · Orphanet · Mitochondrial · 2025
- HGNC:7487HGNC:7487
- Supportive · Orphanet · Mitochondrial · 2025
- HGNC:7489HGNC:7489
- Supportive · Orphanet · Mitochondrial · 2025
- HGNC:7490HGNC:7490
- Supportive · Orphanet · Mitochondrial · 2025
- HGNC:7497HGNC:7497
Where it sits
Other names
9 names
Resolves to: MERRF syndrome
- Also called
- Fukuhara syndromeMERRFmyoclonic epilepsy - ragged red fibresmyoclonus epilepsy and ragged red fibresmyoclonus epilepsy associated with ragged-red fibersmyoclonus epilepsy associated with ragged-red fibresmyoclonus with epilepsy and with ragged Red fibers (MERRF syndrome)myoclonus with epilepsy and with ragged Red fibresmyoclonus with epilepsy and with ragged Red fibres (MERRF syndrome)