severe X-linked mitochondrial encephalomyopathy
Findings
No curated finding names severe X-linked mitochondrial encephalomyopathy yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Severe X-linked mitochondrial encephalomyopathy is an extremely rare mitochondrial respiratory chain disease resulting in a neurodegenerative disorder characterized by psychomotor delay, hypotonia, areflexia, muscle weakness and wasting in the two patients reported to date.
Definition from the Mondo Disease Ontology (MONDO:0010437), read 2026-09-29. CC BY 4.0.
- Inheritance
- X-linked recessive inheritance
- Onset and course
- Infantile onset · Progressive
HPO, annotations 2026-09-02
Features
35 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.
- AreflexiaHPOHP:0001284
- 2 of 2 reported patients
- Very frequent (80% to 99% of cases)
- Developmental regressionHPOHP:0002376
- 2 of 2 reported patients · Infantile onset
- Frequent (30% to 79% of cases)
- Global developmental delayHPOHP:0001263
- 2 of 2 reported patients
- HypotoniaHPOHP:0001252
- 2 of 2 reported patients
- Increased circulating lactate concentrationHPOHP:0002151
- 2 of 2 reported patients
- Frequent (30% to 79% of cases)
- Increased circulating pyruvate concentrationHPOHP:0003542
- 1 of 1 reported patient
Show the remaining 23
- Generalized muscle weaknessHPOHP:0003324
- Very frequent (80% to 99% of cases)
- Increased variability in muscle fiber diameterHPOHP:0003557
- Very frequent (80% to 99% of cases)
- Moderate global developmental delayHPOHP:0011343
- Very frequent (80% to 99% of cases)
- Peripheral neuropathyHPOHP:0009830
- Very frequent (80% to 99% of cases)
- Sensory axonal neuropathyHPOHP:0003390
- Very frequent (80% to 99% of cases)
- Severe muscular hypotoniaHPOHP:0006829
Genes
1 gene
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.
- AIFM1HGNC:8768
- Strong · Labcorp Genetics (formerly Invitae) · X-linked · 2023
- Strong · G2P · X-linked · 2020
- Strong · PanelApp Australia · X-linked · 2025
- Supportive · Orphanet · X-linked · 2021
Where it sits
Other names
4 names
Resolves to: severe X-linked mitochondrial encephalomyopathy
- Also called
- combined oxidative phosphorylation deficiency 6, X-linked recessivecombined oxidative phosphorylation deficiency type 6mitochondrial encephalomyopathy due to combined oxidative phosphorylation defect 6mitochondrial encephalomyopathy due to COXPD6