Mitochondrial Disease

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 220 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 (nuDNA) 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. There may be as many as 5.5 million Canadian adults suffering 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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