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Mitochondria are present in nearly every single cell of our body. Although most of our DNA is kept in the nucleus of each cell, mitochondria have their own set of DNA (mtDNA).
Mitochondria are often considered the ‘power battery’ of our body as their main function is to make energy from oxygen and food. They produce about 90% of the energy that our body needs to function
Mitochondrial diseases (or in short, mito) are a group of chronic genetic disorders which occur when mitochondria fail to produce sufficient energy for our body to function properly.
Therefore, it usually affects body parts that require high levels of energy – which are most of our organs that are used daily.
It is estimated that around one in 5,000 people are affected by mito.
One hallmark of mito is that it is a multiorgan disease.
Most cells in the body have mitochondria. The areas of the body that rely on mitochondria the most are the brain, spinal cord, heart, muscles, kidneys, stomach, intestines and endocrine glands (e.g., thyroid and pancreas). This is because these tissues have a large percentage of mitochondria.
With mito, these organs may not function properly, leading to the following symptoms:
People with mito can develop fatigue very suddenly. They may be unable to tolerate mild exercise. They may also take longer than usual to recover from a minor infection like a cold.
Here are some of the more common mitochondrial syndromes:
Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) MELAS usually starts in childhood to early adulthood. The hallmark of this syndrome is the ‘MELAS attack’: stroke-like episodes with seizures.
Other clinical features include exercise intolerance, short stature, migraine-type headaches, inability to move the eyes, hearing loss, diabetes, digestive problems, heart problems, kidney disease and muscle weakness.
Chronic progressive external ophthalmoplegia (CPEO) CPEO is characterised by weakness of the eye muscles which may cause droopy eyelids and reduced ability to move the eyes. This often occurs in conjunction with other mitochondrial syndromes.
Kearns-Sayre syndrome (KSS) KSS usually starts before age 20. Common symptoms are a gradual inability to move the eyes (CPEO), difficulty seeing in the dark, heart problems and uncoordinated limb movements. Other symptoms may include hearing problems, kidney disease, diabetes or short stature.
Leigh syndrome: subacute necrotising encephalomyopathy Leigh syndrome usually starts in infancy and progression can be fast or slow.
Disease characteristics include vomiting, uncoordinated limb movements, muscle weakness, muscle floppiness or spasticity, seizures, feeding and speech difficulties, hearing loss, abnormal eye movements, visual loss and motor and intellectual regression.
If you feel severe lethargy, weakness, numbness or confusion, please seek treatment as soon as possible. Monitor your health more frequently when ill, even with minor infections like a cold.
Mito can be caused by changes in either the mtDNA or nuclear DNA.
Mito can affect an individual at any age and symptoms vary widely among individuals.
There is no easy test that can be used to diagnose mito. The diagnosis is made based on a combination of the following:
Coming up with a diagnosis can be difficult because many symptoms of mito can mimic that of other diseases. Clinical and blood tests may also be inconclusive and difficult to interpret. However, our understanding of mito has been growing with time.
Unfortunately, most mito do not have curative treatments.
Some patients with certain mito respond well to vitamins and supplements, but the mainstay of treatment would be maintaining good health to prevent worsening of the condition. This would involve good nutrition, regular mild-to-moderate activity and avoidance of infections.