Mitochondrial diseases are an heterogeneous group of rare diseases caused by genetic mutations that prevent the proper functioning of mitochondria, and are usually one of the most common inherited metabolic disorders.

Based on the latest available data, the prevalence of this type of disease is 11.5 per 100,000 inhabitants.

This disease is a genetic disorder that affects mitochondria - cytoplasmic organelles that are responsible for creating more than 90% of the body's energy needed to maintain life and support growth. These dysfunctions can seriously impact health, causing a wide range of symptoms, from muscle weakness to neurological problems.

Due to their fundamental role in metabolism and energy generation, any dysfunction in mitochondria can lead to serious diseases with significant effects on the quality of life of those who suffer from it. The organs most affected are those with a high energy demand, such as skeletal and cardiac muscle, endocrine organs, kidney, retina and central nervous system.

A curious fact about mitochondria is that they have their own DNA, distinct from the nuclear DNA found in cells nucleus. This mitochondrial DNA is inherited exclusively from the mother, meaning that all the mitochondria in your body come from the mitochondria that were present in your mother's egg.

Every year in September, International Mito Patients (IMP) organizes a global campaign that consists of lighting up landmarks in green to raise awareness of the disease. Under the motto Light Up for Mito, the color green lights up building facades around the world.

PH: Elizabeth Quay - Perth, Australia

What causes mitochondrial disease?

Mitochondrial diseases are caused by genetic mutations that can be inherited from one or both parents, or that can occur de novo (new, non-inherited mutations).

Mutations can affect genes in either nuclear DNA or mitochondrial DNA. Specific causes may include:

• Mutations in mitochondrial DNA (mtDNA): These mutations are inherited exclusively from the mother.
• Mutations in nuclear DNA: These mutations can be inherited from both parents.

Under normal circumstances, a child inherits genes in pairs: one gene from the mother and one from the father. A child with a mitochondrial disease does NOT receive a normal gene pair from the parents. The gene has mutated, meaning it has become defective (changed). Learning how a mitochondrial disease has been inherited helps predict the chance of passing the disease on to future children.

Types of inheritance include:

• Autosomal recessive inheritance: This child receives a mutated copy of a gene from each parent.
• Autosomal dominant inheritance: This child receives a mutated copy of a gene from either parent.
• Mitochondrial inheritance: In this unique type of inheritance, mitochondria contain their own DNA.
• Random mutations: Sometimes genes develop a mutation of their own that is not inherited from a parent.

Symptoms of mitochondrial diseases vary widely and can affect multiple body systems because of the importance of mitochondria in all cells.

Some common symptoms include:

• Extreme fatigue: Due to the cells' inability to produce enough energy.
• Muscle weakness and pain: Often affects skeletal and cardiac muscles.
• Neurological problems: These include seizures, coordination problems, developmental delay, and dementia.
• Gastrointestinal problems: Such as intestinal dysmotility and pancreatic insufficiency.
• Heart problems: These include cardiomyopathies and arrhythmias.
• Hearing and vision problems: These include hearing loss and progressive blindness.

Because mitochondrial diseases affect so many different organs and tissues in the body, and patients have so many different symptoms, mitochondrial diseases can be difficult to diagnose.

Diagnosis usually involves:

• History and physical examination: Detailed evaluation of symptoms and family history.
• Genetic testing: Analysis of mutations in mitochondrial and nuclear DNA.
• Muscle biopsy: To examine the function and structure of mitochondria in muscle tissue.
• Metabolic testing: Evaluation of the levels of certain metabolites in blood and urine.
• Imaging studies: Such as magnetic resonance imaging (MRI) to detect abnormalities in affected organs.

There is no cure for the mito:

But treatments can help manage symptoms and improve quality of life. Treatment approaches include:

• Supplement therapy: Coenzyme Q10, L-carnitine, and other vitamins and minerals to support mitochondrial function.
• Medications: To manage specific symptoms such as seizures, cardiac arrhythmias, or gastrointestinal problems.
• Physical and occupational therapies: To improve muscle strength and coordination.
• Energy conservation: Don't do too much in a short period of time. Pace yourself.
• Nutrition: Specific diets that can help maximize energy production.
• Other treatments. These may include speech therapy, respiratory therapy, and occupational therapy.

Mitochondrial diseases represent a significant challenge for both, patients and healthcare professionals, due to their complexity and variety of symptoms. A multidisciplinary and personalized approach is essential for effective management of these diseases, and continued research offers hope for new treatments and, eventually, a cure.

As we advance our knowledge of mitochondria, we move closer to improving the quality of life for those suffering from mitochondrial diseases. Continuing to explore is not only vital for those suffering from these diseases, but also to expanding our understanding of how our body functions at a cellular level.