ΜΕLAS Syndrome / Mitochondrial encephalopathy, lactic acidosis and stroke – like episodes

This syndrome is included in mitochondrial myopathies, with maternal mutation origin or rarely they are sporadic cases. It is characterized by three differential points: 1. Stroke – like episodes earlier than 40 years old, 2. Encephalopathy with seizures and/or dementia, 3. Mitochondrial myopathy, lactic acidosis with ragged-red fibers. It presents with unknown prevalence, but in some countries like Finland more often.  

Symptoms

  • Stroke – like symptoms
  • Dementia
  • Epilepsy
  • Lactic acidosis
  • «ragged-red» fibers 
  • Exercise intolerance
  • hemiparesis (often)
  • vision loss or hemianopia (often)
  • recurrent headaches (often)
  • hearing impairment (often)
  • muscle weakness (often)
  • peripheral neuropathy (sometimes)
  • learning disability (sometimes)
  • memory impairment (sometimes)
  • recurrent vomiting (sometimes)
  • short stature (sometimes)

Rare manifestations are: basal ganglia calcification, myoclonus, ataxia, episodic altered consciousness, gait disturbance, depression, anxiety, psychotic disorders, diabetes, protic atrophy, pigmentary retinopathy, progressive external opthlalmoplegia, motor developmental delay, cardiomyopathy, cardiac conduction abnormalities, nephropathy, vitiligo.  

Diagnosis

  • Clinical examination  
  • Molecular test
  • Biochemical tests 
  • ΜRI and spectroscopy  
  • Echo and electrocardiogram  
  • Muscle biopsy

Management 

There is no cure yet, but it is symptomatic and a multidisciplinary team is mandatory, including a neurologist, cardiologist, endocrinologist, audiologist, ophthalmologist, physical and occupational therapist and psychologist and social worker. 

Usually a special diet is suggested and in particular, antioxidants and cofactors. There are indications for L- arginine, citrulline, coenzyme Q10, creatine, and L-carnitine, but the need of more clinical trials to prove safety and efficacy is essential.  

Useful links 

Support Groups 

  1. https://www.mitoaction.org/
  2. https://www.umdf.org/

References 

  1. El-Hattab AW, Adesina AM, Jones J, Scaglia F. MELAS syndrome: Clinical manifestations, pathogenesis, and treatment options. Mol Genet Metab. 2015 ;116 (1-2): 4-12.
  2. Hsu YR, Yogasundaram H, Parajuli N, Valtuille L, Sergi C, Oudit GY. MELAS syndrome and cardiomyopathy: linking mitochondrial function to heart failure pathogenesis. Heart Fail Rev. 2016; 21 (1): 103-116.
  3. Pia S, Lui F. Melas Syndrome. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2020.
  4. Murakami H, Ono K. Brain Nerve. 2017 ;69 (2): 111-117.
  5. Koenig MK, Emrick L, Karaa A, et al. Recommendations for the Management of Strokelike Episodes in Patients With Mitochondrial Encephalomyopathy, Lactic Acidosis, and Strokelike Episodes. JAMA Neurol. 2016; 73 (5): 591-594.
  6. Finsterer J. Mitochondrial metabolic stroke: Phenotype and genetics of stroke-like episodes. J Neurol Sci. 2019;400:135-141.

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