Rare Ophthalmology News

Disease Profile

Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

Adolescent

ICD-10

G71.3

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

MELAS; MELAS syndrome

Categories

Congenital and Genetic Diseases; Ear, Nose, and Throat Diseases; Eye diseases;

Summary

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) affects many parts of the body, particularly the brain and nervous system (encephalo-) and muscles (myopathy). Symptoms typically begin in childhood and may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. People with MELAS can also have a buildup of lactic acid in their bodies that can lead to vomiting, abdominal pain, fatigue, muscle weakness, and difficulty breathing. The genes associated with MELAS are located in mitochondrial DNA and therefore follow a maternal inheritance pattern (also called mitochondrial inheritance). MELAS can be inherited from the mother only, because only females pass mitochondrial DNA to their children. In some cases, MELAS results from a new mutation that was not inherited from a person's mother.[1]

Symptoms

The signs and symptoms of MELAS often appear in childhood following a period of normal development. Early symptoms may include muscle weakness and pain, recurrent headaches, loss of appetite, vomiting, and seizures. Most affected individuals experience stroke-like episodes beginning before age 40. These episodes may involve temporary muscle weakness on one side of the body, altered consciousness, vision abnormalities, seizures, and severe headaches resembling migraines. Repeated stroke-like episodes can progressively damage the brain, leading to vision loss, problems with movement, and a loss of intellectual function.[1]

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.[1]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. 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.
  • Orphanet lists international laboratories offering diagnostic testing for this condition.

    Organizations

    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Organizations Providing General Support

        Learn more

        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.

        Where to Start

        • MedlinePlus Genetics contains information on Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes. This website is maintained by the National Library of Medicine.
        • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

          In-Depth Information

          • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
          • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes. Click on the link to view a sample search on this topic.

            References

            1. Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Genetics Home Reference. November 2006; https://ghr.nlm.nih.gov/condition/mitochondrial-encephalomyopathy-lactic-acidosis-and-stroke-like-episodes. Accessed 10/17/2011.
            2. Salvatore DiMauro and Michio Hirano. MELAS. GeneReviews. November 21, 2013; https://www.ncbi.nlm.nih.gov/books/NBK1233/. Accessed 12/4/2013.
            3. Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Genetics Home Reference. November 2006; https://ghr.nlm.nih.gov/condition/mitochondrial-encephalomyopathy-lactic-acidosis-and-stroke-like-episodes. Accessed 12/4/2013.

            Rare Ophthalmology News

            Medical Terms Other Names
            Learn More:
            HPO ID
            80%-99% of people have these symptoms
            Abnormal mitochondria in muscle tissue
            0008316
            Aphasia
            Difficulty finding words
            Losing words
            Loss of words

            [ more ]

            0002381
            Aplasia/Hypoplasia of the cerebral white matter
            Absent/small cerebral white matter
            Absent/underdeveloped cerebral white matter

            [ more ]

            0012429
            Dementia
            Dementia, progressive
            Progressive dementia

            [ more ]

            0000726
            EEG abnormality
            0002353
            Increased serum lactate
            0002151
            Lactic acidosis
            Increased lactate in body
            0003128
            Migraine
            Intermittent migraine headaches
            Migraine headache
            Migraine headaches

            [ more ]

            0002076
            Muscle weakness
            Muscular weakness
            0001324
            Ragged-red muscle fibers
            0003200
            Stroke-like episode
            0002401
            Widened cerebral subarachnoid space
            0012766
            30%-79% of people have these symptoms
            Anxiety
            Excessive, persistent worry and fear
            0000739
            Ataxia
            0001251
            Basal ganglia calcification
            0002135
            Bilateral tonic-clonic seizure
            Grand mal seizures
            0002069
            Depressivity
            Depression
            0000716
            Encephalopathy
            0001298
            Fluctuations in consciousness
            0007159
            Focal-onset seizure
            Seizure affecting one half of brain
            0007359
            Gait disturbance
            Abnormal gait
            Abnormal walk
            Impaired gait

            [ more ]

            0001288
            Hemiparesis
            Weakness of one side of body
            0001269
            Impaired visuospatial constructive cognition
            0010794
            Increased CSF lactate
            0002490
            Increased CSF protein
            0002922
            Memory impairment
            Forgetfulness
            Memory loss
            Memory problems
            Poor memory

            [ more ]

            0002354
            Myoclonus
            0001336
            Myopathy
            Muscle tissue disease
            0003198
            Recurrent paroxysmal headache
            0002331
            Sensorineural hearing impairment
            0000407
            Short attention span
            Poor attention span
            Problem paying attention

            [ more ]

            0000736
            Short stature
            Decreased body height
            Small stature

            [ more ]

            0004322
            Visual loss
            Loss of vision
            Vision loss

            [ more ]

            0000572
            Vomiting
            Throwing up
            0002013
            5%-29% of people have these symptoms
            Agenesis of corpus callosum
            0001274
            Anemia
            Low number of red blood cells or hemoglobin
            0001903
            Bipolar affective disorder
            Bipolar disorder
            0007302
            Cardiac conduction abnormality
            0031546
            Cerebral cortical atrophy
            Decrease in size of the outer layer of the brain due to loss of brain cells
            0002120
            Concentric hypertrophic cardiomyopathy
            0005157
            Constipation
            0002019
            Diarrhea
            Watery stool
            0002014
            Dilated cardiomyopathy
            Stretched and thinned heart muscle
            0001644
            Distal peripheral sensory neuropathy
            0007067
            Elevated brain lactate level by MRS
            0012707
            Erythema
            0010783
            Exercise intolerance
            Decreased ability to exercise
            Inability to exercise

            [ more ]

            0003546
            Failure to thrive
            Faltering weight
            Weight faltering

            [ more ]

            0001508
            Fever
            0001945
            Focal segmental glomerulosclerosis
            0000097
            Global developmental delay
            0001263
            Hypertrichosis
            0000998
            Hypoplasia of the corpus callosum
            Underdevelopment of part of brain called corpus callosum
            0002079
            Intestinal pseudo-obstruction
            0004389
            Mixed demyelinating and axonal polyneuropathy
            0007327
            Motor delay
            0001270
            Nephropathy
            0000112
            Optic atrophy
            0000648
            Peripheral axonal neuropathy
            0003477
            Personality changes
            Personality change
            0000751
            Pigmentary retinopathy
            0000580