Many people with MELAS have a buildup of lactic acid in their bodies (lactic acidosis). This can lead to vomiting, abdominal pain, extreme fatigue, muscle weakness, and difficulty breathing. Involuntary muscle spasms, impaired muscle coordination, hearing loss, heart and kidney problems, diabetes, and hormonal imbalances may also occur.
The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
|Signs and Symptoms||Approximate number of patients (when available)|
|Abnormality of mitochondrial metabolism||90%|
|Aplasia/Hypoplasia of the cerebellum||50%|
|Attention deficit hyperactivity disorder||50%|
|Cerebral cortical atrophy||50%|
|Decreased body weight||50%|
|Decreased nerve conduction velocity||50%|
|Nausea and vomiting||50%|
|Sensorineural hearing impairment||50%|
|Type II diabetes mellitus||50%|
|Visual field defect||50%|
|Abnormality of neuronal migration||7.5%|
|Abnormality of retinal pigmentation||7.5%|
|Abnormality of temperature regulation||7.5%|
|Abnormality of the genital system||7.5%|
|Abnormality of the liver||7.5%|
|Abnormality of the macula||7.5%|
|Abnormality of the pinna||7.5%|
|Abnormality of the renal tubule||7.5%|
|Abnormality of visual evoked potentials||7.5%|
|Congestive heart failure||7.5%|
|Delayed skeletal maturation||7.5%|
|Feeding difficulties in infancy||7.5%|
|Hypopigmented skin patches||7.5%|
|Neurological speech impairment||7.5%|
|Premature loss of teeth||7.5%|
|Primary adrenal insufficiency||7.5%|
|Skeletal muscle atrophy||7.5%|
|Sudden cardiac death||7.5%|
|Type I diabetes mellitus||7.5%|
|Bilateral sensorineural hearing impairment||-|
|Cortical visual impairment||-|
|Generalized tonic-clonic seizures||-|
|Left ventricular hypertrophy||-|
|Progressive sensorineural hearing impairment||-|
|Ragged-red muscle fibers||-|
The Genetic Testing Registry (GTR) is a centralized online resource for information about genetic tests. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional. Please see a list of laboratories offering the genetic test for MELAS.
The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.
Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.
Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
New Rare Disease Patient Video Series
July 18, 2016
Nutritional Interventions in Primary Mitochondrial Disorders: Developing an Evidence Base
Tuesday, December 2, 2014 -
Wednesday, December 3, 2014
Location: NIH Campus, Bethesda, MD
Description: The goal of this meeting is to explore the use of nutritional interventions, including dietary supplements, in primary mitochondrial disorders (PMD); identify gaps in knowledge; develop a research agenda; and identify research opportunities to promote an evidence base for the use of nutritional interventions in primary mitochondrial disorders.
Contact: Kathryn Camp, MS, RD, CSP,(301) 435-3608, firstname.lastname@example.org
Co-funding Institute(s): Office of Dietary Supplements, Office of Rare Diseases Research
2013 Neurobiology of Disease in Children Symposium: Mitochondrial Disease
Wednesday, October 30, 2013 -
Wednesday, October 30, 2013
Location: Austin, TX
Description: The topic for the 2013 NDC Symposium is Mitochondrial Disease. The NDC Symposium is a forum for preeminent investigators assembled to discuss recent accomplishments and future directions with a large group of child neurologists, program officers from the National Institutes of Health, and members of dedicated foundations and associations.
Co-funding Institute(s): National Institute of Neurological Disorders and Stroke, Office of Rare Diseases Research
Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question
My brother was diagnosed with MELAS several years ago. His wife informed me that his doctor said that all 3 of us children inherited the gene from our mother. His diagnosis was confirmed after viewing our mother's autopsy reports. How probable is it that myself or our other brother will be affected by this disease? See answer
Is there a link between mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS) and a person who is not really strong? See answer
My doctor has ordered the MELAS test, but it is very expensive and the labs hardly take any insurance. Are there any other options? See answer