MELAS: clinical features

Genetics and pathology

• This is usually caused by the m.3243A>G tRNALeu (UUR) mutation
• The pathology is characterised by ragged-red fibers and type 1 fiber dominance
• The mitochondria are abnormal

References

1. McFarland R, Turnbull DM. Batteries not included: diagnosis and management of mitochondrial disease. J Intern Med 2009; 265:210-228.
2. Koo B, Becker LE, Chuang S, et al. Mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS): clinical, radiological, pathological, and genetic observations. Ann Neurol 1993; 34:25-32.
3. Fan HC, Lee HF, Yue CT, Chi CS. Clinical characteristics of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Life (Basel) 2021; 11:1111. 
4. Nesbitt V, Pitceathly RD, Turnbull DM, et al. The UK MRC Mitochondrial Disease Patient Cohort Study: clinical phenotypes associated with the m.3243A>G mutation-implications for diagnosis and management. JNNP 2013; 84:936-938.
5. Iizuka T, Sakai F, Suzuki N, Hata T, Tsukahara S, Fukuda M, Takiyama Y. Neuronal hyperexcitability in stroke-like episodes of MELAS syndrome. Neurology 2002; 59:816-824.
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Related checklists

• MELAS: MRI features
• MELAS stroke-like episodes (SLEs): clinical features
• MELAS stroke-like episodes (SLEs): radiological features
• MELAS: management