| MELAS clinical feature | Suggested HPO term | HP ID | Frequency / onset notes | Evidence source |
|---|---|---|---|---|
| Stroke-like episodes | Stroke-like episode | HP:0002401 | >90% of patients in Finsterer 2020; typically a core feature of MELAS, often before age 40 in classic diagnostic criteria; all 39 patients in Gao 2024 initially presented with stroke-like episodes | (pqac-00000020, pqac-00000004) |
| Seizures | Seizure | HP:0001250 | 76% in Finsterer 2020; 88.1% in MELAS group in Cox 2023 | (pqac-00000020, pqac-00000009) |
| Lactic acidosis | Lactic acidosis | HP:0003128 | Hallmark biochemical abnormality; elevated plasma/CSF lactate and lactate peak on MRS; not quantified in retrieved evidence for symptom frequency | (pqac-00000002, pqac-00000006) |
| Migraine / headache | Headache | HP:0002315 | Headache 50% in Finsterer 2020; recurrent headache is also part of classic diagnostic criteria; migraine-like headache reported in MELAS cohorts | (pqac-00000020, pqac-00000012) |
| Vomiting | Vomiting | HP:0002013 | 55% in Finsterer 2020; recurrent vomiting is part of classic diagnostic criteria | (pqac-00000020, pqac-00000012) |
| Muscle weakness / myopathy / exercise intolerance | Proximal muscle weakness / Mitochondrial myopathy / Exercise intolerance | HP:0003701 / HP:0003200 / HP:0003546 | Muscle weakness 48% in Finsterer 2020; proximal muscle weakness and exercise intolerance were predominant in Xu 2024 cohort; onset variable, often childhood to young adulthood | (pqac-00000020, pqac-00000017) |
| Sensorineural hearing loss | Sensorineural hearing impairment | HP:0000407 | Diabetes and deafness associated with intermediate heteroplasmy (about 50–70%) in Na 2024; hearing loss was the first symptom in 51.6% of symptomatic non-MELAS vs 24.4% of MELAS in Cox 2023; exact overall MELAS frequency not quantified in retrieved evidence | (pqac-00000002, pqac-00000009) |
| Diabetes mellitus | Diabetes mellitus | HP:0000819 | Reported in 10–24% in Finsterer 2020; late-onset MELAS had diabetes in 69.2% vs 13.8% standard-onset in Cox 2023 | (pqac-00000020, pqac-00000009) |
| Short stature | Short stature | HP:0004322 | >25% of cases in Finsterer 2020 | (pqac-00000020) |
| Cortical blindness / vision loss | Cortical visual impairment / Cortical blindness | HP:0100704 / HP:0007956 | Visual loss 52% in Finsterer 2020; cortical vision loss listed as a typical phenotype in Na 2024; vision loss in first stroke-like episode helped define atypical MELAS in Alves 2023 summary | (pqac-00000020, pqac-00000006) |
| Cerebellar atrophy | Cerebellar atrophy | HP:0001272 | 68% (40/59 imaging studies) in Zheng 2023; also highly discriminatory for stroke-like episodes vs acute ischemic stroke in Khasminsky 2023 | (pqac-00000000, pqac-00000021) |
| Basal ganglia calcification | Basal ganglia calcification | HP:0002135 | 67% (6/9 patients with CT) in Zheng 2023 | (pqac-00000000) |


*Table: This table maps core MELAS manifestations to suggested Human Phenotype Ontology terms and summarizes frequency or onset information from the retrieved evidence. It is useful for structured phenotype curation in a disease knowledge base.*