MELAS Syndrome

A neurodegenerative disorder

MELAS syndrome is caused by problems with the genetic material in body cells. Specifically, it is due to defects in the genetic material in mitochondria, the parts of cells that generate energy for the body to do its work.

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. It is known, however, that the genetic defect most often involved in MELAS is passed down through the mother’s side of the family.

Symptoms
MELAS stands for:

• Mitochondrial myopathy – weakness of muscles throughout the body
• Encephalopathy – disease of the central nervous system
• Lactic Acidosis – abnormal build-up of lactic acid, normally a waste product, in the body
• Stroke – occurs when the blood supply to part of the brain is cut off by disease, and brain cells die.

These conditions cause many symptoms which are often debilitating. Strokes cause brain damage, leading to seizures, numbness, or partial paralysis. The encephalopathy causes tremors, muscle spasms, blindness, deafness, and may lead to dementia. Myopathy causes difficulty walking, moving, eating, and speaking.

Diagnosis
In many individuals with MELAS syndrome, a stroke, or similar symptoms such as headache, vomiting, or seizures, is the first clue that something is wrong. The first stroke 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, 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 computed tomography (CT scan) or magnetic resonance imaging (MRI), can look for signs of brain damage from stroke.

Treatment
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, 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.

Information for this article was taken from:
Scaglia, F. (2002). MELAS syndrome. eMedicine, accessed at http://www.emedicine.com/ped/topic1406.htm