Mitochondrial Diseases & Mitochondrial Dysfunction

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Mitochondrial Diseases & Mitochondrial Dysfunction

Mitochondrial disease is a group of disorders caused by dysfunctional mitochondria – mitochondria that don’t work properly. It can affect energy intensive systems within the body including:

  • liver
  • kidneys
  • pancreas
  • brain
  • digestive tract
  • muscles

It can affect multiple systems in the body including the liver, kidneys, pancreas, brain and digestive tract. The eyes, inner ear, muscles and blood may also be affected. Click here to view an illustration.

There are currently over 300 illnesses associated with mitochondrial dysfunction, and the list is growing. Every 30 minutes, a child is born with mitochondrial disease and about 1 in 4,000 people has the disease. 

Each condition is the result of a genetic mutation – a specific change in the genetic material of the mitochondria. The mutations occur in the mitochondrial DNA (mtDNA) or nuclear genes (nDNA) and cause the mitochondria to fail. At least 1 in 200 individuals harbor a mitochondrial mutation.

Healthy mitochondria convert oxygen and the sugar, fat and protein from the foods we eat into energy-rich molecules called ATP (adenosine triphosphate).

Energy from ATP is needed to carry out vital functions that our bodies need to survive and thrive. The mitochondrion is very susceptible to damage. When mitochondria are not functioning properly, their impacts on the body can be devastating.

To view the body system affected by the primary mitochondrial disease, click here.

During the production of ATP, your mitochondria produce waste called free radicals. This toxic waste can cause specific changes (mutations) in the genetic material of the mitochondria that damage the mitochondrion itself and can cause cell dysfunction and disease. Mitochondrial disease results when the production of cellular energy is defective.

Primary mitochondrial disease (PMD) is genetically inherited and diagnosed by identifying mutations on mitochondrial DNA (mtDNA) or nuclear DNA (nDNA) that result in mitochondrial dysfunction.

PMDs can occur due to germline mutations mtDNA and/or nDNA genes encoding ETC proteins. Point mutations can occur in any of the mtDNA’s 37 genes encoding 13 proteins or the 1,000 nDNA genes, which are essential for optimal ETC function.

Some common primary mitochondrial diseases include:

  • MELAS
  • NARP
  • Leigh’s Syndrome
  • MERRF
  • LHON
  • Kern-Sayre Syndrome
  • MNGIE
  • Aplers

We estimate that over 10,000 Canadian’s suffer from primary mitochondrial diseases – most are yet to be diagnosed.

Secondary mitochondrial dysfunction (SMD) can be caused by genes encoding neither function nor production of specific proteins, oxidative stress, drug toxicity or environmental factors.

Distinguishing whether mitochondrial dysfunction is inherited or acquired is extremely challenging. The best method for making this distinction is still poorly understood.

One of the most reliable (but not all-encompassing) tools is comprehensive molecular testing (genome sequencing) of both mDNA and nDNA which, at least in some cases, can ultimately distinguish between PMD and SMD.

Unfortunately, there is no single test that can determine whether you do or do not have mitochondrial disease.

Mitochondrial disease is difficult to diagnose because it affects different people in different ways. It is estimated millions of Canadians suffer from diseases in which mitochondrial dysfunction is involved.

These include diabetes, diseases of the heart, kidney and liver, Alzheimer’s, ALS, Parkinson’s, autism, cancer, blindness, deafness, chronic fatigue, infertility and more.

There is no cure for mitochondrial disease – yet.

MitoCanada is transforming the outlook for people with mitochondrial disease by raising awareness, offering knowledge and support to patients, families and caregivers and, funding transformational research.

Who is at risk?
The more energy a cell needs, the more mitochondria they have. Because our brain, heart, liver, kidneys, digestive tract and muscles need the most energy, they are the most susceptible to mitochondrial disease.

General Rule: If three or more organ systems are involved, mitochondrial disease may be suspected.

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Source: https://mitocanada.org/mitochondrial-disease/

Mitochondrial Malfunctions

Mitochondrial Diseases & Mitochondrial Dysfunction

Within each of the body’s tiny cells are dozens to tens of dozens of even tinier mitochondria. These organelles (“little organs”) convert fuel from the food we eat into energy.

At least that’s how it’s supposed to work — for some the situation is far different. Every year 800 babies are born in America with some form of inherited mitochondrial disease.

Any organ may be affected — brain, muscles, heart, liver, nerves, eyes, ears and kidneys — at any age.

Debilitating and potentiallyfatal, mitochondrial disorders mimic many other illnesses, making them notoriouslytricky to diagnose. And because they’re caused by an array of inborn errors ofmetabolism, all of which are rare, they’re not easy to study.

Related research has shown, however, that even people born with healthy mitochondria may develop impairment. In fact, mitochondrial dysfunctions are often hidden in other conditions including Huntington's and Alzheimer’s, muscular dystrophy, and even autism.

Evolving together

Mayo Clinic researchers are pursuing a range of investigative approaches to better understand and predict the impact of mitochondrial malfunctions, with the goal of helping patients. Here, we touch on four of these scientists and their research efforts.

Mitochondria not only power us up, they’re at the center of intracellular communications and stress responses. They help determine which cells should grow and which should die. And, because they generate most of our body heat, they deserve our gratitude when north winds blow.

On Mayo Clinic’s Minnesota campus, Eugenia Trushina, Ph.D. leads a laboratory investigating mitochondrial dynamics in the brain.

Layla Khalili, laboratory technician, with researcher Eugenia Trushina, Ph.D.

Cells have lots of types of organelles, but mitochondria are special, having evolved from bacteria that came to live symbiotically inside larger cells — one changing the other to our ultimate advantage. “Because mitochondria were originally an independent species, they have very unique behavior,” she says.

They also have their own DNA.

A mitochondrion sends DNA-coded instructions to its nucleus, and vice versa.

To complicate the picture even more, while a cell has just one nucleus with one genome, it has many mitochondria, each of which carries multiple genome copies. And these copies typically vary within a cell.

Inside the same person, some mitochondrial genomes might be healthy, but others defective, and different cells can have different proportions of affected mitochondria within them.

Using patient samples to make senseof it all

“Right now, it’s really difficult for some patients with rare genetic diseases to finally get an answer about what condition they have,” explains Devin Oglesbee, Ph.D., who co-directs the Mayo Clinic Mitochondrial Disease Biobank, which opened in 2009. “We’re trying to expand their options.”

Blood-derived samples from a large number of patients and their family members — people with and without mitochondrial disorders — are banked along with non-identifying donor information age, sex, diagnosis and medication.

Each sample remains in its subzero vault until a researcher requests it, months, years or even decades later.

Both the Mitochondrial Disease Clinic and the North American Mitochondrial Disease Consortium (originally spearheaded by investigators at Columbia University in New York) contribute to the effort.

Devin Oglesbee, Ph.D.

Born and educated in Oregon, Dr.

Oglesbee first joined Mayo Clinic as a postdoctoral fellow, later becoming co-director of the Biochemical Genetics Laboratory, which focuses on creating methods to detect and monitor inborn errors of metabolism (including the development of screening tests for newborns). Now, he and his collaborators can use banked samples to look for biomarkers — specifically metabolites — that show up at levels outside the normal range in patients with mitochondrial disorders.

Metabolites are small compounds sugars, lipids, amino acids etc. that are involved in the chemical reactions taking place within our cells. Basically, our DNA makes proteins, and those proteins generate metabolites.

Scientists can take a sort of snapshot of themetabolites in a sample and compare it to the profiles of other samples.

Biomarkersare the compounds that stand out; they can be used to detect and diagnosedisease, often before symptoms appear, and they can help point to the mosteffective treatments.

“At Mayo Clinic, we’re capable of just immediately translating those new discoveries into a marker for patients,” Dr. Oglesbee says. For example, a clinical test is now available for a metabolite called growth differentiation factor 15 or GDF15 — a new arrow in the quiver for evaluating patients with potential mitochondrial disorders.

“There has also been a lot of work,” continues Dr. Oglesbee, “on using these biobanked specimens for regenerative medicine.” In one such approach, Timothy Nelson, M.D., Ph.D., is generating stem cells from patients with mitochondrial disorders with the goal of identifying therapies to halt or reverse the progression of diseases arising from faulty genes.

From Alpers disease to Wolfram syndrome, mitochondrial diseases caused by inborn errors of metabolism are evaluated by

Mayo's Mitochondrial Disease Clinic.

Stress and energy balance

Acute casesof mitochondrial disease can be straightforward to diagnose, but most childrenand adults present to their pediatricians or GPs with multiple, complexsymptoms that don’t seem to add up. As a physician in the Mitochondrial Disease Clinic, EvaMorava-Kozicz, M.D., Ph.D. knows that her patients haveoften beaten a long, rocky and confusing path to reach her door.

“The children — they’re between life and death,” she says, “and the adults have this chronic, invalidating disease that affects all organs and all systems, even the brain. It’s just really a very, very unfair disease.”

Dr. Morava focuses on describing new mitochondrial disorders, including, recently, a disease associated with hearing loss.

“Of course, I wish that meant that by discovering it I could take it away,” but at least now this particular combination of symptoms should raise suspicion of the gene defect, and a targeted diagnostic approach is in the making.

She also studies stress-related mood disorders using mice with lower than normal mitochondrial complex 1 activity. Complex 1 is the enzyme catalyzing the first reaction of mitochondrial respiration — the conversion of fuel from food into energy for our cells.

Her interest in mood disorders began whentreating a 16-year-old patient who’d been admitted to a psychiatric hospitalafter being diagnosed with a conversion disorder (anxiety that’s been”converted” into physical symptoms).

“She did have psychosis, itwas true,” says Dr. Morava, “but she also couldn’t walk.”

Because muscle and nerve cells have especially high energy needs, muscular and neurological problems are common features of mitochondrial disorders, and it turned out that this patient had a riboflavin-responsive complex I deficiency.

After being supplemented with this B vitamin, she recovered. It’s notunusual for a clinician to mistakenly conclude that a mood disorder has led apatient to, as Dr.

Morava explains, “make-believe that they have a metabolicdisorder,” when, actually, the metabolic disorder led to the mood disorder.

Before joining Mayo Clinic, Dr. Morava, who was born and educated in Hungary, spent a decade in the Radboud University Medical Center. There she began a collaboration with a neuroscientist who later became her husband, Tamas Kozicz, M.D., Ph.D. Now together at Mayo Clinic, they and their teams are working to figure out why the complex-1-deficient mice are more vulnerable to stress.

Eva Morava-Kozicz, M.D., Ph.D., and Tamas Kozicz, M.D., Ph.D.

These mice have only mild mitochondrialdysfunction, but when stressed, they exhibit clinical symptoms that includemood disorders. In essence, the mice have to balance their power use becausethere’s not quite enough energy to go around. When stressed, that balance isupset and they become crippled by anxiety.

When caring for patients, “there are a lot ofdietary interventions we use to improve quality of life,” says Dr. Morava, “andthere are some treatable metabolic disorder types.

” Avoiding stressors canhelp, as can certain supplements, depending on the genetic defect.

Somemedications can alleviate symptoms, while others can make them worse; antidepressants,for instance, actually have metabolic side effects, and thus can exacerbatesymptoms.

Transporting energy

Mitochondrial diseases the ones Dr. Morava treats arise from defects in genes for mitochondrial proteins. But because mitochondria are gatekeepers — critical cellular checkpoints that contribute to health — their dysfunction impacts other disorders ranging from stroke to cardiomyopathy to diabetes.

Mitochondria are dynamic; they split, they join, and they reposition themselves strategically within cells experiencing metabolic or environmental stresses. In muscle cells, they interconnect a wire grid distributing power throughout a city. In nerve cells, they’re more energy transport vehicles, moving along axons interstates.

1. Found in all types of human cells, mitochondria play a critical role in the generation of the metabolic energy required to sustain life. 2. Cells with high demand for energy, such as muscle cells, have a large number of mitochondria. 3. Mitochondria can also travel within cells, such as along the length of neuronal axons, in response to the cells' need.

Totrack mitochondria during the early stages of Alzheimer’s disease,Dr. Trushina uses live cell imaging assays and three-dimensional electronmicroscopy reconstruction. These techniques are traffic cameras, followingmitochondria as they move within nerve cells to match energy demand to energysupply.

“A motor neuron can have an axon that’s one meter long, and mitochondria have to travel from the cell body…to the distal parts of axons to dock at the sites of synapse, at the sites where energy’s needed…and then they have to travel all the way back to the cell body for repair or degradation,” explains Dr. Trushina, “so it’s quite a journey.”

Originally from Russia, Dr. Trushina first came to Mayo Clinic as a postdoc to study the molecular mechanisms of Huntington’s disease.

Early on, she happened across a compound that had been earmarked to treat high cholesterol, and was struck by an idea: even though the compound didn’t work as a cholesterol drug, it did protect neurons from mis-timed cell death.

Because mitochondria regulate cell death through an event termed mitochondrial outer membrane permeabilization (a.k.a., cell suicide), maybe, she thought, mitochondria could be a therapeutic target for neurodegenerative diseases.

After monitoring mitochondrial traffic for more than a decade, Dr. Trushina and her team have developed promising analogues of that original, neuroprotective compound. These small molecules not only reduce levels of the sticky amyloid beta peptides that build up to form plaques in the synapses between nerve cells in the brains of Alzheimer’s patients, they actually avert cognitive decline.

Thesymptoms of Alzheimer’s only reveal themselves when the disease has alreadycaused irreversible damage.

Clinicians need good methods to diagnose patientsearlier, and effective treatments to keep amyloid plaques from getting afoothold. Working to meet these requirements, Dr.

Trushina is profiling metabolites, searching out early biomarkers ofmitochondrial dysfunction at the same time that she’s bringing Alzheimer’sdrugs to clinical trials.

Because mitochondria play such important rolesin our cells, their optimal function is foundational for health, while theirdysfunction is associated with most chronic conditions, including aging. Whenit all comes down to it, “everything converges on mitochondria,” saysDr. Trushina.

To that end, Mayo Clinic has established the Mitochondrial Care Center, in which researchers and physicians work together to develop future therapies and care approaches for patients with mitochondrial conditions. In addition to the researchers in this article, the center includes co-directors Eduardo Chini, M.

D.,Ph.D. and Ralitza Gavrilova, M.D.,as well as Ian Lanza, Ph.D. who focuses on mitochondrial physiology; Wolfdieter Springer, Ph.D., whose drug-target studies span several related diseases including Parkinson’s;  and Joao Passos, Ph.D. who researches mitochondria and its relation to senescent cells and aging.

– Megan McKenzie, May 2019

Source: https://discoverysedge.mayo.edu/2019/08/05/mitochondrial-malfunctions/

Mitochondrial genetic disorders

Mitochondrial Diseases & Mitochondrial Dysfunction
People with mitochondrial genetic disorders can present at any age with almost any affected body system. While some conditions may only affect a single organ, many involve multiple organ systems including the brain, muscles, heart, liver, nerves, eyes, ears and/or kidneys. Symptom severity can also vary widely.

The most common signs and symptoms include:[1][2]

  • Poor growth
  • Loss of muscle coordination
  • Muscle weakness
  • Seizures
  • Autism
  • Problems with vision and/or hearing
  • Developmental delay
  • Learning disabilities
  • Heart, liver, and/or kidney disease
  • Gastrointestinal disorders
  • Diabetes
  • Increased risk of infection
  • Thyroid and/or adrenal abnormalities
  • Autonomic dysfunction
  • Dementia

The United Mitochondrial Disease Foundation's website features a comprehensive list of possible symptoms (click here to see this information) and symptoms categorized by type of mitochondrial genetic disorder (click here to access this page).

Last updated: 1/26/2015

Do you have updated information on this disease? We want to hear from you.

Cause Cause

Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria. Most DNA (hereditary material that is passed from parent to child) is packaged within the nucleus of each cell (known as nuclear DNA).

However, mitochondria (the structures in each cell that produce energy) contain a small amount of their own DNA, which is known as mitochondrial DNA.[1][2]

When the mitochondria are not working properly, the body does not have enough energy to carry out its normal functions.

This can lead to the variety of health problems associated with mitochondrial genetic disorders.[1][2]

Last updated: 1/26/2015

Inheritance Inheritance

Mitochondrial genetic disorder can be inherited in a variety of manners depending on the type of condition and the location of the disease-causing change (mutation). Those caused by mutations in mitochondrial DNA are transmitted by maternal inheritance.

[1][3] Only egg cells (not sperm cells) contribute mitochondria to the next generation, so only females can pass on mitochondrial mutations to their children. Conditions resulting from mutations in mitochondrial DNA can appear in every generation of a family and can affect both males and females.

In some cases, the condition results from a new (de novo) mutation in a mitochondrial gene and occurs in a person with no history of the condition in the family.

Mitochondrial genetic disorders caused by mutations in nuclear DNA may follow an autosomal dominant, autosomal recessive, or X-linked pattern of inheritance.

[1][3] In autosomal dominant conditions, one mutated copy of the responsible gene in each cell is enough to cause signs or symptoms of the condition. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new mutations in the gene.

These cases occur in people with no history of the disorder in their family. A person with an autosomal dominant condition has a 50% chance with each pregnancy of passing along the altered gene to his or her child.

When a condition is inherited in an autosomal recessive manner, a person must have a change in both copies of the responsible gene in each cell. The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers.

Carriers typically do not show signs or symptoms of the condition.

When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier each of the parents, and a 25% chance to not have the condition and not be a carrier.

A condition is considered X-linked if the mutated gene that causes the condition is located on the X chromosome, one of the two sex chromosomes (the Y chromosome is the other sex chromosome). Women have two X chromosomes and men have an X and a Y chromosome.

X-linked conditions can be X-linked dominant or X-linked recessive. The inheritance is X-linked dominant if one copy of the altered gene in each cell is sufficient to cause the condition.

Women with an X-linked dominant condition have a 50% chance of passing the condition on to a son or a daughter with each pregnancy. Men with an X-linked dominant condition will pass the condition on to all of their daughters and none of their sons.

The inheritance is X-linked recessive if a gene on the X chromosome causes the condition in men with one gene mutation (they have only one X chromosome) and in females with two gene mutations (they have two X chromosomes).

A woman with an X-linked condition will pass the mutation on to all of her sons and daughters. This means that all of her sons will have the condition and all of her daughters will be carriers. A man with an X-linked recessive condition will pass the mutation to all of his daughters (carriers) and none of his sons.

Last updated: 1/26/2015

Diagnosis Diagnosis

Unfortunately, mitochondrial genetic disorders can be difficult to diagnose, and many affected people may never receive a specific diagnosis. They are often suspected in people who have a condition that effects multiple, unrelated systems of the body.

In some cases, the pattern of symptoms may be suggestive of a specific mitochondrial condition. If the disease-causing gene(s) associated with the particular condition is known, the diagnosis can then be confirmed with genetic testing.

[1][5]

If a mitochondrial genetic disorder is suspected but the signs and symptoms do not suggest a specific diagnosis, a more extensive work-up may be required.

In these cases, a physician may start by evaluating the levels of certain substances in a sample of blood or cerebrospinal fluid. Other tests that can support a diagnosis include:[1]

When possible, confirming a diagnosis with genetic testing can have important implications for family members. Identifying the disease-causing gene(s) will give the family information about the inheritance pattern and the risk to other family members. It will also allow other at-risk family members to undergo genetic testing.[1]

For more information regarding the diagnosis of mitochondrial genetic disorders, please visit the United Mitochondrial Disease Foundation's “Getting a Diagnosis” Web page.

GeneReviews also provides information on establishing a diagnosis of a mitochondrial disorder. Click on the link to view the article on this topic.

Last updated: 1/26/2015

  • 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.

Treatment Treatment

Treatment for mitochondrial genetic disorders varies significantly the specific type of condition and the signs and symptoms present in each person. The primary aim of treatment is to alleviate symptoms and slow the progression of the condition.

For example, a variety of vitamins and other supplements have been used to treat people affected by mitochondrial conditions with varying degrees of success. Other examples of possible interventions include medications to treat diabetes mellitus, surgery for cataracts, and cochlear implantation for hearing loss.

[4][1]

For more general information about the treatment of mitochondrial genetic disorders, please visit GeneReviews.

Last updated: 1/26/2015

Find a Specialist Find a Specialist

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease.

You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals.

You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Research Research

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.

  • ClinicalTrials.gov lists trials that are related to Mitochondrial genetic disorders. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies. Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Organizations 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.

Learn More 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.

  • MitoAction provides information on this condition for patients and caregivers.
  • The Cleveland Clinic Web site has an information page on Mitochondrial genetic disorders. Click on the Cleveland Clinic link to view this page.
  • The United Mitochondrial Disease Foundation has an information page on Mitochondrial genetic disorders.
  • 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.
  • MitoAction provides information on this condition for health care professionals.
  • Nature Education’s Scitable provides a comprehensive explanation of mitochondrial DNA and the conditions that can be associated with mitochondrial DNA mutations.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Mitochondrial genetic disorders. Click on the link to view a sample search on this topic.

News & Events News & Events

  • Nutritional Interventions in Primary Mitochondrial Disorders: Developing an Evidence Base Tuesday, December 2, 2014 – Wednesday, December 3, 2014 Location: NIH Campus, Bethesda, MDDescription: 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, campkm@od.nih.govCo-funding Institute(s): Office of Dietary Supplements, Office of Rare Diseases Research

Source: https://rarediseases.info.nih.gov/diseases/7048/mitochondrial-genetic-disorders

Mitochondrial Disease: Read About Treatment and Symptoms

Mitochondrial Diseases & Mitochondrial Dysfunction

*Mitochondiral myopathies facts medical Charles Patrick Davis, MD, PhD

  • Mitochondrial disease includes a group of neuromuscular diseases caused by damage to intracellular structures that produce energy, the mitochondria; disease symptoms usually involve muscle contractions that are weak or spontaneous.
  • There is no specific treatment for mitochondrial diseases (myopathies).
  • The prognosis varies according to the disease type; in general, these diseases are progressive and can cause death.
  • Research into treatments and other disease aspects is ongoing; there are several organizations devoted to understanding and treating these relatively rare disorders.

What are mitochondrial myopathies?

Mitochondrial myopathies are a group of neuromuscular diseases caused by damage to the mitochondria—small, energy-producing structures that serve as the cells' “power plants.

” Nerve cells in the brain and muscles require a great deal of energy, and thus appear to be particularly damaged when mitochondrial dysfunction occurs.

Some of the more common mitochondrial myopathies include Kearns-Sayre syndrome, myoclonus epilepsy with ragged-red fibers, and mitochondrial encephalomyopathy with lactic acidosis and stroke- episodes.

What are the symptoms of mitochondrial myopathies?

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The symptoms of mitochondrial myopathies include muscle weakness or exercise intolerance, heart failure or rhythm disturbances, dementia, movement disorders, stroke- episodes, deafness, blindness, droopy eyelids, limited mobility of the eyes, vomiting, and seizures.

The prognosis for these disorders ranges in severity from progressive weakness to death. Most mitochondrial myopathies occur before the age of 20, and often begin with exercise intolerance or muscle weakness. During physical activity, muscles may become easily fatigued or weak. Muscle cramping is rare, but may occur.

Nausea, headache, and breathlessness are also associated with these disorders.

Is there any treatment for mitochondrial disease?

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Although there is no specific treatment for any of the mitochondrial myopathies, physical therapy may extend the range of movement of muscles and improve dexterity. Vitamin therapies such as riboflavin, coenzyme Q, and carnitine (a specialized amino acid) may provide subjective improvement in fatigue and energy levels in some patients.

What is the prognosis for mitochondrial disease?

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The prognosis for patients with mitochondrial myopathies varies greatly, depending largely on the type of disease and the degree of involvement of various organs. These disorders cause progressive weakness and can lead to death.

What research is being done for mitochondrial disease?

The NINDS conducts and supports research on mitochondrial myopathies. The goals of this research are to increase scientific understanding of these disorders and to find ways to effectively treat, prevent, or potentially cure them.

Heart Disease: Causes of a Heart Attack See Slideshow

References

“NINDS Mitochondrial Myopathies Information Page.” National Institute of Neurological Disorders and Stroke. 16 Dec. 2011.

Source: https://www.medicinenet.com/mitochondrial_disease/article.htm

Diseases – MM – Top Level | Muscular Dystrophy Association

Mitochondrial Diseases & Mitochondrial Dysfunction

Download our Mitochondrial Myopathies (MM) Fact Sheet

What causes mitochondrial myopathies?

Mitochondrial myopathies are caused by mutations, or changes, in genes — the cells' blueprint for making proteins. They are inheritable, although they can occur with no family history, and they often affect members of the same family in different ways. For more, see Causes/Inheritance.

What is the progression of mitochondrial myopathies?

The age of onset and progression of mitochondrial myopathy varies greatly from type to type. See Types of Mitochondrial Myopathies for more information about the course of each disease.

What is the status of research on mitochondrial myopathies?

MDA-funded scientists have identified many of the genetic defects that cause mitochondrial diseases, and they have used that knowledge to create animal models of many of them. Understanding the genetic defects that cause mitochondrial myopathies opens up the possibility of developing treatments for these diseases. See Research for more.

Source: https://www.mda.org/disease/mitochondrial-myopathies

Mitochondrial Disease

Mitochondrial Diseases & Mitochondrial Dysfunction

Mitochondrial disease, or mitochondrial disorder, refers to a group of disorders that affect the mitochondria, which are tiny compartments that are present in almost every cell of the body. The mitochondria’s main function is to produce energy.

More mitochondria are needed to make more energy, particularly in high-energy demand organs such as the heart, muscles, and brain. When the number or function of mitochondria in the cell are disrupted, less energy is produced and organ dysfunction results.

Depending on which cells within the body have disrupted mitochondria, different symptoms may occur.

Mitochondrial disease can cause a vast array of health concerns, including fatigue, weakness, metabolic strokes, seizures, cardiomyopathy, arrhythmias, developmental or cognitive disabilities, diabetes mellitus, impairment of hearing, vision, growth, liver, gastrointestinal, or kidney function, and more. These symptoms can present at any age from infancy up until late adulthood.

Every 30 minutes, a child is born who will develop a mitochondrial disorder by age 10. Overall, approximately 1 in every 4,300 individuals in the United States has a mitochondrial disease. Given the various potential presentations that may occur, mitochondrial disease can be difficult to diagnosis and is often misdiagnosed.

There are various methods to examine if an individual has mitochondrial disease. These include genetic diagnostic testing, genetic or biochemical tests in affected tissues, such as muscle or liver, and other blood or urine based biochemical markers. However, our knowledge is still growing and we do not yet know all of the genes that could potentially cause mitochondrial disease.

Mitochondria are unique in that they have their own DNA called mitochondrial DNA, or mtDNA. Mutations in this mtDNA or mutations in nuclear DNA (DNA found in the nucleus of a cell) can cause mitochondrial disorder. Environmental toxins can also trigger mitochondrial disease.

Mitochondrial disorder symptoms include:

  • Poor growth
  • Loss of muscle coordination, muscle weakness
  • Neurological problems, including seizures
  • Autism spectrum disorder, represented by a variety of ASD characteristics
  • Visual and/or hearing problems
  • Developmental delays, learning disabilities
  • Heart, liver or kidney disease
  • Gastrointestinal disorders, such as severe constipation
  • Diabetes
  • Respiratory disorders
  • Increased risk of infection
  • Thyroid and/or adrenal dysfunction
  • Dysfunction of the autonomic nervous system
  • Neuropsychological changes or dementia characterized by confusion, disorientation and memory loss

Currently there is no highly effective treatment or cure for mitochondrial disorder. The management of mitochondrial disease is supportive therapy, which may include nutritional management, exercise and/or vitamin or amino acid supplements.

Knowing the underlying cause of your or your child’s condition will help your medical team determine the best course of treatment. Mitochondrial Medicine at Children's Hospital of Philadelphia (CHOP) works closely with your primary care physician, neurologist, and other specialists to manage your day-to-day medical needs.

Our team will provide relevant mitochondrial disease counseling your child’s diagnosis, including an overview of mitochondrial disease features and genetics.

Your child’s neurologist or primary care physician will manage the day-to-day medical concerns associated with mitochondrial disease.

Long-term care may involve a variety of specialists, including neurologists, endocrinologists, ophthalmologists, audiologists, cardiologists and nephrologists.

For patients with mitochondrial disease with no known genetic cause, yearly follow-up appointments are typically recommended as mutations in new genes causing mitochondrial disease are discovered all the time.

Source: https://www.chop.edu/conditions-diseases/mitochondrial-disease

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