MELAS syndrome
Findings
No curated finding names MELAS syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
MELAS (Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke) syndrome is a rare progressive multisystemic disorder characterized by encephalomyopathy, lactic acidosis, and stroke-like episodes. Other features include endocrinopathy, heart disease, diabetes, hearing loss, and neurological and psychiatric manifestations.
Definition from the Mondo Disease Ontology (MONDO:0010789), read 2026-09-29. CC BY 4.0.
Features
87 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.
- Abnormal mitochondria in muscle tissueHPOHP:0008316
- Very frequent (80% to 99% of cases)
- AphasiaHPOHP:0002381
- Very frequent (80% to 99% of cases)
- Aplasia/Hypoplasia of the cerebral white matterHPOHP:0012429
- Very frequent (80% to 99% of cases)
- DementiaHPOHP:0000726
- Very frequent (80% to 99% of cases)
- EEG abnormalityHPOHP:0002353
- Very frequent (80% to 99% of cases)
- Increased circulating lactate concentrationHPOHP:0002151
- Very frequent (80% to 99% of cases)
- Lactic acidosisHPOHP:0003128
- Very frequent (80% to 99% of cases)
- MigraineHPOHP:0002076
- Very frequent (80% to 99% of cases)
- Muscle weaknessHPOHP:0001324
- Very frequent (80% to 99% of cases)
- Ragged-red muscle fibersHPOHP:0003200
- Very frequent (80% to 99% of cases)
- SeizureHPOHP:0001250
- Very frequent (80% to 99% of cases)
- Stroke-like episodeHPOHP:0002401
- Very frequent (80% to 99% of cases)
Show the remaining 75
- Widened cerebral subarachnoid spaceHPOHP:0012766
- Very frequent (80% to 99% of cases)
- AnxietyHPOHP:0000739
- Frequent (30% to 79% of cases)
- AtaxiaHPOHP:0001251
- Frequent (30% to 79% of cases)
- Basal ganglia calcificationHPOHP:0002135
- Frequent (30% to 79% of cases)
- Bilateral tonic-clonic seizureHPOHP:0002069
- Frequent (30% to 79% of cases)
- DepressionHPOHP:0000716
- Frequent (30% to 79% of cases)
Genes
6 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:7459HGNC:7459
- Supportive · Orphanet · Mitochondrial · 2021
- MT-CO1HGNC:7419
- Supportive · Orphanet · Mitochondrial · 2021
- MT-CO2HGNC:7421
- Supportive · Orphanet · Mitochondrial · 2021
- MT-ND1HGNC:7455
- Supportive · Orphanet · Mitochondrial · 2021
- MT-ND5HGNC:7461
- Supportive · Orphanet · Mitochondrial · 2021
- MT-ND6HGNC:7462
Where it sits
- Narrower terms (10)
- MELAS syndrome caused by mutation in MTND1
- MELAS syndrome caused by mutation in MTND5
- MELAS syndrome caused by mutation in MTND6
- MELAS syndrome caused by mutation in MTTC
- MELAS syndrome caused by mutation in MTTH
- MELAS syndrome caused by mutation in MTTK
- MELAS syndrome caused by mutation in MTTL1
- MELAS syndrome caused by mutation in MTTQ
- MELAS syndrome caused by mutation in MTTS1
- MELAS syndrome caused by mutation in MTTS2
Other names
4 names
Resolves to: MELAS syndrome
- Also called
- mitochondrial encephalomyopathy, lactic acidosis and strokemitochondrial encephalomyopathy, lactic acidosis and stroke-like episodesmitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodesmitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes