MELAS Syndrome

What is MELAS Syndrome?

MELAS Syndrome is a rare genetic disorder that results in stroke and dementia. MELAS stands for Mitochondrial Encephalopathy, Lactic acidosis, and Stroke. The condition begins in childhood between the ages of two and fifteen years and mostly affects the nervous system and muscles.

MELAS syndrome is caused by mutations in the genetic material (DNA) in the mitochondria and is inherited from the mother. An affected mother will pass MELAS syndrome on to all her children but only her daughters will pass the mutation on to their children. The condition was first distinguished by the name MELAS Syndrome in 1984.

MELAS syndrome may be diagnosed using a brain or muscle biopsy. A muscle biopsy will show characteristic ragged red fibers while a brain biopsy will show stroke-like changes. Brain imaging techniques such as magnetic resonance imaging (MRI) may also be used to look for stroke-like lesions and magnetic resonance spectroscopy (MRS) may be used to look for a lactate peak in the brain. The condition affects men and women equally.

What are the Symptoms of MELAS Syndrome?

Brain dysfunction (encephalopathy) with headaches and seizures, abnormal thinking (dementia), muscle disease with a build-up of lactic acid in the blood (lactic acidosis), temporary local paralysis, hormonal imbalances, loss of appetite and recurrent vomiting, heart and kidney problems, loss of bowel control, and hearing loss.

How is MELAS Syndrome Treated?

Anti-convulsant drugs are used to control seizures associated with MELAS syndrome, cochlear implants have been used to treat sensorineural deafness, moderate treadmill training may improve aerobic activity and lower resting lactate levels, and the use of oral arginine has been shown to reduce the recurrence of stroke-like episodes when administered during the asymptomatic period.

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Last Reviewed:
October 10, 2016
Last Updated:
August 30, 2017