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Published on: October 10, 2025
Screening for MELAS mutations in young patients with stroke of undetermined origin
Adriana Bastos Conforto1, Fabio Iuji Yamamoto, Sueli Mieko Oba-Shinjo
1Neurology Division, Hospital das Clínicas/São Paulo University, São Paulo, SP, Brazil. abconf@yahoo.com
Purpose:
It has been suggested that mitochondrial disease may be responsible for a substantial proportion of strokes of indetermined origin. We have preliminarily screened for MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) mutations in young patients with cryptogenic strokes.
Method:
The mitochondrial mutations A3243G and T3271C were investigated in 38 subjects aged less than 46 years. Group 1: 15 patients with cryptogenic strokes; Group 2: 3 patients with diagnosis of MELAS syndrome, including stroke-like episodes; Group 3: 20 healthy subjects.
Results:
The A3243G mutation was absent in all subjects in Groups 1 and 3 but was present in all subjects in Group 2.
Conclusion:
Our results do not support screening for these mutations to diagnose oligosymptomatic forms of MELAS in cryptogenic strokes in the absence of other features of the syndrome. We suggest that clinical findings should guide mitochondrial genetic testing.
Insights
This study found no evidence of MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) mutations in young patients with cryptogenic strokes. Genetic testing for these mitochondrial mutations is not recommended without other MELAS symptoms.
Area of Science:
- Neurology
- Genetics
- Mitochondrial Diseases
Background:
- Mitochondrial diseases, such as MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes), are increasingly suspected in strokes of unknown origin.
- Cryptogenic strokes in young individuals warrant investigation into potential underlying genetic causes.
Purpose of the Study:
- To investigate the prevalence of specific mitochondrial mutations (A3243G and T3271C) in young patients presenting with cryptogenic strokes.
- To determine if screening for MELAS mutations is beneficial for diagnosing oligosymptomatic forms in patients with unexplained strokes.
Main Methods:
- A cohort of 38 subjects was analyzed, including 15 patients with cryptogenic strokes, 3 diagnosed MELAS patients, and 20 healthy controls.
- Mitochondrial DNA mutations A3243G and T3271C were specifically screened in all participants.
- Subjects were all under 46 years of age.
Main Results:
- The A3243G mitochondrial mutation was detected in all patients diagnosed with MELAS syndrome (Group 2).
- This specific mutation was absent in all patients with cryptogenic strokes (Group 1) and healthy controls (Group 3).
- The T3271C mutation was not detailed in the results.
Conclusions:
- The findings do not support routine genetic screening for MELAS mutations (A3243G and T3271C) in young patients with cryptogenic strokes lacking other characteristic MELAS symptoms.
- Clinical presentation and other features of MELAS syndrome should guide decisions for mitochondrial genetic testing.
- Further research may be needed to explore other genetic or non-genetic causes of cryptogenic strokes in this demographic.
