Mitochondrial disease

What is Mitochondrial Disease?

Mitochondrial disease occurs when the mitochondria in the body’s cells can no longer produce adequate energy. This can lead to the failure of individual cells and, eventually, the malfunction of entire organ systems. Given that mitochondria are involved in nearly every bodily function, this disease can affect multiple organs and systems simultaneously, making it difficult to diagnose and treat.

The condition is typically inherited and can be caused by mutations in either the mitochondrial DNA (mtDNA) or the nuclear DNA (nDNA) that controls mitochondrial function. There are also environmental factors, like toxins, that can damage mitochondria and contribute to the disease. The severity and specific symptoms of mitochondrial disease vary significantly from one individual to another, making each case unique.

The Importance of Mitochondria in the Human Body

Mitochondria are tiny but essential structures within almost every cell of the human body. Known as the “powerhouses” of the cell, they are responsible for producing up to 90% of the energy the body needs to sustain life and support essential functions. From your brain to your muscles, every organ relies on mitochondria for the energy required to perform daily tasks.

In a healthy body, mitochondria convert the food we eat and the oxygen we breathe into adenosine triphosphate (ATP), the energy molecule that fuels everything from muscle contraction to nerve transmission. However, when mitochondria malfunction due to genetic mutations or environmental damage, this process can be severely disrupted. The result is mitochondrial disease, a condition that affects cellular energy production and can lead to multi-organ failure.

Every 30 minutes, a child is born who will develop mitochondrial disease by the time they reach 10 years old.

Mitochondrial disease

The Impact of Mitochondrial Disease on the Body

The disease can affect any part of the body, but it tends to hit organs that require a lot of energy the hardest. This includes the heart, brain, muscles, and nerves, but other organs such as the liver, pancreas, and kidneys can also be affected.

Symptoms of Mitochondrial Disease

Brains Symptoms

Developmental delays
Seizures
Learning disabilities
Migraines
Stroke-like episodes
Dementia

The brain is highly dependent on mitochondrial energy, so when mitochondria fail, it can lead to severe neurological symptoms. Children with mitochondrial disease often exhibit developmental delays, difficulty learning, and are at higher risk for seizures.

Muscles Symptoms

Muscle weakness
Hypotonia (decreased muscle tone)
Exercise intolerance
Cramps and muscle pain

Muscle cells require large amounts of ATP for contraction. When mitochondria are not working correctly, muscles can become weak, cramp easily, and tire quickly. This often leads to motor function issues and physical limitations in affected individuals.

Nerves Symptoms

Peripheral neuropathy (numbness, tingling, and pain in the extremities)
Autonomic dysfunction (problems with heart rate, digestion, and blood pressure)
Loss of reflexes

Nerve cells also require a lot of energy, and mitochondrial disease can damage the peripheral nervous system, leading to pain, weakness, and difficulty with movement.

Heart Symptoms

Cardiomyopathy (weakening of the heart muscle)
Heart block (abnormal heart rhythms)
Heart failure

Since the heart is one of the most energy-demanding organs in the body, mitochondrial disease often leads to serious heart problems. Cardiomyopathy and heart failure are common and can be life-threatening without proper management.

Liver and Kidneys Symptoms

Liver failure
Renal tubular dysfunction
Low blood sugar

Both the liver and kidneys rely on healthy mitochondria to perform their detoxifying and regulatory functions. Mitochondrial disease can lead to kidney dysfunction and liver failure, contributing to severe metabolic imbalances like low blood sugar.

Pancreas Symptoms

Diabetes
Pancreatic failure

Mitochondrial dysfunction in the pancreas can lead to insulin production issues, causing diabetes and other metabolic disorders.

Eyes and Ears Symptoms

Vision loss
Hearing loss
Strabismus (crossed eyes)
Retinitis pigmentosa (degenerative eye disease)

The sensory organs are also affected, which can lead to vision and hearing impairments. Optic atrophy (degeneration of the optic nerve) is common in patients with this condition.

Understanding the Genetic Basis of Mitochondrial Disease

Mitochondrial disease is primarily a genetic condition, passed down from parents to their children. Mitochondrial DNA is inherited only from the mother, meaning if a woman has a mutation in her mitochondrial DNA, all her children will inherit it. However, mitochondrial disease can also be caused by mutations in nuclear DNA, which is inherited from both parents.

There are over 250 genes associated with mitochondrial function, and mutations in any of these genes can result in mitochondrial disease. This genetic complexity is part of what makes the disease so difficult to diagnose and treat. For a more in-depth look into the genetics of mitochondrial disease, check out our mission page to learn about our research efforts.

When three or more organ systems are affected, it could be a critical indicator of mitochondrial disease.

Types of Mitochondrial Disease

There are many types of mitochondrial diseases, each presenting a unique combination of symptoms. Some of the most common include:

Leigh Syndrome: A severe neurological disorder that primarily affects infants and children. Symptoms include loss of motor skills, seizures, and respiratory problems.
MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes): This condition is characterized by stroke-like episodes, muscle weakness, and learning disabilities.
Kearns-Sayre Syndrome: A condition that causes progressive weakness in the muscles that control eye movement, as well as heart problems and hearing loss.

Each of these conditions is caused by different genetic mutations, and each presents its own challenges for treatment and diagnosis.

Differents Diagnosing

Due to the wide range of symptoms and the overlap with other conditions, diagnosing mitochondrial disease can be challenging. Most diagnoses are made by specialists such as neurologists, geneticists, or cardiologists.

Common Diagnostic Tests:

Blood and Urine Tests: To measure levels of amino acids, lactate, pyruvate, and other substances that indicate mitochondrial dysfunction.
DNA Testing: Genetic testing is often used to identify mutations in mitochondrial DNA or nuclear DNA.
Muscle Biopsy: In some cases, a muscle biopsy is performed to study the mitochondria in muscle tissue and assess their function.

Since mitochondrial disease affects multiple systems, a diagnosis typically requires a comprehensive evaluation from a team of specialists.

Resources

Resources for Families

The Liam Foundation is committed to supporting families affected by mitochondrial disease by providing resources, access to specialists, and community support. Whether you’re looking for a doctor, seeking information about treatments, or simply need emotional support, we’re here to help.

At The Liam Foundation, we are dedicated to raising awareness, funding research, and providing critical resources to those affected by mitochondrial disease. Together, we can work towards finding better treatments and, one day, a cure.

For more information, visit our What We Do and Get Involved by donating to our cause and the research for a cure for the Mitochondrial Disease.

If you have any question you can also contact us with the form and a member of our team will respond to you as soon as possible.

What is Mitochondrial Disease?

The Importance of Mitochondria in the Human Body