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Autism associated with the mitochondrial DNA G8363A transfer RNA(Lys) mutation
W D Graf1, J Marin-Garcia, H G Gao
1Department of Pediatrics, University of Washington, Seattle, USA. wgraf@chmc.org
Journal of Child Neurology
|June 27, 2000
Summary
A mitochondrial DNA mutation (G8363A) in the transfer RNA (tRNA)-Lys gene is linked to diverse neurologic disorders, including autism and Leigh syndrome, in one family. This suggests mitochondrial mutations may underlie some autism cases.
Area of Science:
- Neurogenetics
- Mitochondrial Biology
- Developmental Neuroscience
Background:
- Mitochondrial DNA mutations are implicated in various neurological disorders.
- Heterogeneous phenotypes can arise from specific mitochondrial genetic defects.
- Autism Spectrum Disorder (ASD) etiology is complex and multifactorial.
Observation:
- A family presented with distinct neurological conditions, including autism and Leigh syndrome.
- One child exhibited autism symptoms with language regression, hyperactivity, and seizures, despite normal MRI and lactate levels.
- The sister presented with Leigh syndrome, characterized by ataxia, myoclonus, seizures, and cognitive regression, with specific MRI and biochemical findings.
Findings:
- The G8363A mutation in the mitochondrial transfer RNA (tRNA)-Lys gene was identified in both affected siblings.
- Higher mutant mitochondrial DNA loads (82-86%) were found in the sister with Leigh syndrome compared to the brother with autism (60-61%).
- This indicates a potential genotype-phenotype correlation and varying tissue expression of the mitochondrial mutation.
Implications:
- The study suggests the G8363A mitochondrial DNA mutation is pathogenic and can cause a spectrum of neurological disorders.
- This finding proposes that mitochondrial point mutations may be a contributing factor to autism in some individuals.
- Further research into mitochondrial dysfunction in neurodevelopmental disorders is warranted.