Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes Syndrome, also known as MELAS, is a rare mitochondrial condition where the body is not able to make enough mitochondrial proteins needed to make energy. Mitochondria are parts of a cell that help turn the energy we get from food into energy that the body can use. They are also important in the communication between body parts and creating other materials the body needs. Mitochondrial conditions can cause a variety of signs and symptoms in many parts of the body, particularly those that use a lot of energy like muscles and the brain.
- MELAS syndrome
MT-ND1, MT-ND5, MT-TH, MT-TL1, MT-TV
Cause and Genetics
MELAS is an inherited genetic condition, meaning it is passed down in a family. MELAS is caused by changes in the mitochondrial genome (mtDNA) or set of DNA contained in the mitochondria of a cell. Mitochondria are inherited from the mother through her eggs. People typically do not inherit any mitochondria from sperm, making it very unlikely for mitochondrial conditions to be passed down from a father. Both males and females can have MELAS.
Frequency - More Information
While MELAS is a rare disorder, it is one of the more common mitochondrial conditions. It is estimated that approximately one in 4000 people have MELAS, but the exact frequency varies by country. MELAS may also be underdiagnosed.
Affected Biological Gender
Both Male and Female
Signs and Symptoms
MELAS can cause a range of signs and symptoms. These can present at any age, but most often appear in childhood following a period of normal development. The exact features, onset, and severity can vary widely among people with this condition, even among members of the same family. Always check with your provider if new symptoms appear or you are concerned.
Signs and symptoms may include:
- Weakness and pain
- Recurrent headache
- Loss of appetite
- Uncontrolled movements (ataxia)
- Mental health conditions
- Gastrointestinal or kidney conditions
Most people with MELAS have a stroke-like episode before age 40. These episodes often involve temporary muscle weakness on one side of the body, called hemiparesis, altered consciousness, vision changes, seizures and severe headaches that can seem like a migraine.
Repeated stroke-like episodes can lead to brain damage, vision loss, problems with movement, and loss of intellectual abilities (dementia).
Most people with MELAS have a buildup of lactic acid in their bodies, a condition called lactic acidosis. Increased acidity in the blood can lead to vomiting, abdominal pain, extreme tiredness or fatigue, muscle weakness, and difficulty breathing. Less commonly, people with MELAS may experience involuntary muscle spasms called myoclonus, impaired muscle coordination (ataxia), hearing loss, heart and kidney problems, diabetes, and hormonal imbalances.
MELAS can be diagnosed by:
- Muscle biopsy showing ragged red fibers (RRF)
- SDH staining showing overabundance of mitochondria in smooth muscle and blood vessels
- Measuring biochemical markers in blood or the cerebrospinal fluid (fluid surrounding the brain and spinal cord)
- Brain studies and imaging looking for changes in the structure of the brain or seizure activity (MRI, MRS, EEG)
- Heart studies looking for rhythm changes (EKG)
- Performing a genetic test to look for changes in the genes known to cause MELAS
Newborn Screening: Recommended Uniform Screening Panel (RUSP)
Newborn Screening - More Information
Treatment and Management
As of 2022, there is no FDA-approved therapy for MELAS. Treatment and management of MELAS is symptomatic and supportive.
This may include:
- Traditional medications for seizures (antiepileptic drugs)
- Physical therapy and aerobic exercise to support muscle function
- Traditional treatment of heart conditions
- Hearing aids or cochlear implants for hearing loss
- Avoidance of mitochondrial toxins like certain drugs, tobacco, and alcohol
- Mitochondrial supplements like riboflavin and Coenzyme Q10
- Traditional treatment of diabetes
- Traditional treatment for migraines
Since illness with fever can trigger presentation of MELAS symptoms, people with MELAS are encouraged to receive standard childhood vaccinations, flu vaccine, and pneumococcal vaccine.
Type of Specialists and Clinicians
- Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes – About the Disease – The National Institutes of Health
- MELAS Syndrome – National Organization for Rare Disorders)
Connecting with others impacted by a rare disease allows for vital information to be shared about day-to-day life, prevents isolation, and gives hope. Please contact MitoAction for peer support opportunities at 888-MITO-411 or email firstname.lastname@example.org.
Other resources we recommend are:
- New Patient Kit for Mitochondrial Conditions
- Planning for Emergencies
- Monthly Expert Series
- Energy in Action Podcast
MitoAction does not provide medical advice, diagnosis, treatment, or legal advice. It is essential that all those living with or caring for someone with a Mitochondrial or FAOD disease have an emergency protocol letter. These letters, which are written and signed by a doctor, share details about prescribed treatment during crises and in emergency room settings. Always check with your doctor if you or your child has concerns as everyone may present with symptoms differently. Before beginning any treatment or therapy, please consult with your physician.
Last Updated: 11/15/2022