MELAS Syndrome Symptoms and Treatment

MELAS syndrome (characterized by mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) is a progressive neurodegenerative disorder caused by mutations in mitochondrial DNA. Mitochondria are the structures inside our cells that are largely responsible for producing the energy the cells need to do their work. Mitochondria have their own DNA, which is always inherited from the mother. However, MELAS syndrome is often not actually inherited; the mutation in this disorder commonly occurs spontaneously.

Because the disease is poorly understood and can be difficult to diagnose, it is not yet known how many individuals have developed MELAS throughout the world. The syndrome affects all ethnic groups and both males and females.

The disease often is fatal. Since there is no cure for MELAS syndrome, medical care is largely supportive.

Mitochondria TEM
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Because defective mitochondria exist in all the cells of patients with MELAS syndrome, many kinds of symptoms can develop that are often debilitating. The hallmark of this disease is the occurrence of stroke-like symptoms characterized by sudden neurological symptoms, such as weakness involving one side of the body or visual disturbances. These are not true strokes, hence the term "stroke-like."

Other common symptoms related to encephalopathy are recurrent migraine-like headaches, seizures, vomiting, and cognitive impairment. Patients with MELAS often have short structure and hearing loss. In addition, myopathy (muscle disease) causes difficulty in walking, moving, eating, and speaking.

Affected individuals usually begin showing symptoms between the ages of 4 and 40.


In many individuals with MELAS syndrome, stroke-like symptoms, along with recurrent headache, vomiting, or seizures, are the first clue that something is wrong. The first stroke-like episode usually occurs in childhood, between the ages of 4 and 15 years, but it may occur in infants or in young adults. Prior to the first stroke, the child may be slow to grow and develop, or have learning disabilities or attention deficit disorder.

Tests can check the level of lactic acid in the blood and cerebrospinal fluid. Blood tests can check for an enzyme (creatine kinase) present in muscle disease. A muscle sample (biopsy) can be tested for the most common genetic defect present in MELAS. Brain-imaging studies, such as a computed tomography (CT) scan or magnetic resonance imaging (MRI), can show brain abnormalities during these stroke-like episodes. Unlike in patients with strokes, however, the blood vessels in the brains of those with MELAS are usually normal.


Unfortunately, there is as yet no treatment to stop the damage done by MELAS syndrome, and the outcome for individuals with the syndrome is usually poor. Moderate treadmill training can help improve the endurance of individuals with myopathy.

Metabolic therapies, including dietary supplements, have shown benefits for some individuals. These treatments include coenzyme Q10, L-carnitine, arginine, phylloquinone, menadione, ascorbate, riboflavin, nicotinamide, creatine monohydrate, idebenone, succinate, and dichloroacetate. Whether these supplements will help all individuals with MELAS syndrome is still being studied.

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  1. Schon EA, Dimauro S, Hirano M. Human mitochondrial DNA: roles of inherited and somatic mutations. Nat Rev Genet. 2012;13(12):878-90. doi:10.1038/nrg3275

  2. De luca R, Russo M, Leonardi S, et al. Advances in the treatment of MELAS syndrome: could cognitive rehabilitation have a role?. Appl Neuropsychol Adult. 2016;23(1):61-4. doi:10.1080/23279095.2014.960522

  3. Lorenzoni PJ, Werneck LC, Kay CS, Silvado CE, Scola RH. When should MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) be the diagnosis?. Arq Neuropsiquiatr. 2015;73(11):959-67. doi:10.1590/0004-282X20150154

Additional Reading
  • Kaufmann P, Engelstad K, Wei Y, et al. Natural history of MELAS associated with mitochondrial DNA m.3243A>G genotype. Neurology 2011; 77:1965.
  • Scaglia, F. (2002). MELAS syndrome. eMedicine.