Related Experiment Video
Updated: Jun 24, 2026

Modeling Mitochondrial Disease Using Brain Organoids: A Focus on Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes
Published on: October 10, 2025
Clinical heterogeneity in ethylmalonic encephalopathy
Nicole Pigeon1, Philippe M Campeau, Denis Cyr
1Department of Pediatrics, Université de Sherbrooke, Quebec, Canada.
Ethylmalonic encephalopathy, a rare metabolic disorder, presents differently even in identical twins. This study highlights the varied clinical outcomes and neurological impacts of this condition.
Area of Science:
- Biochemistry
- Genetics
- Neurology
Background:
- Ethylmalonic encephalopathy (EE) is an inborn error of metabolism.
- EE is characterized by developmental delay, regression, petechiae, orthostatic acrocyanosis, and chronic diarrhea.
Observation:
- Monochorionic twins presented with infantile hypotonia and were diagnosed with EE.
- Both twins had compound heterozygous missense mutations in the ETHE1 gene.
- MRI revealed white matter, corpus callosum, and basal ganglia abnormalities in both.
Findings:
- Despite shared genetics and diagnosis, the twins exhibited distinct clinical courses at age 10.
- One twin developed severe spastic quadriparesis and aphasia after an episode of coma.
- The other twin showed milder pyramidal signs and retained speech, illustrating significant clinical heterogeneity.
Implications:
- This case study underscores the variable phenotypic expression of ethylmalonic encephalopathy.
- Understanding this heterogeneity is crucial for accurate diagnosis and prognosis, even in genetically identical individuals.
- Further research into factors influencing EE's variable presentation is warranted.
More Related Videos
08:22A Novel Strategy Combining Array-CGH, Whole-exome Sequencing and In Utero Electroporation in Rodents to Identify Causative Genes for Brain Malformations
Published on: December 1, 2017
07:08A High Throughput, Multiplexed and Targeted Proteomic CSF Assay to Quantify Neurodegenerative Biomarkers and Apolipoprotein E Isoforms Status
Published on: October 20, 2016
Related Concept Videos
Hepatic Encephalopathy
Encephalitis l: Introduction
Inborn Errors of Metabolism
Encephalitis ll: Pathophysiology
Alzheimer Disease l: Introduction
Cerebral Edema ll: Pathophysiology