WHAT ARE MITOCHONDRIAL DISORDERS?Mitochondrial disorders occur in approximately 1 of every 4,000 individuals. Such disorders result from failures of the mitochondria, which are specialized compartments in the cell that act as the energy source for daily body activity. When mitochondria fail, less and less energy is generated within the cell. As a result, whole systems begin to fail, and the health of the person in whom this is happening is severely compromised. The disease primarily affects children, but can affect adults as well.
Diseases of the mitochondria appear to cause the most damage to cells of high energy demand such as the brain, heart, liver, skeletal muscles, kidneys, and the endocrine, gastrointestinal, and respiratory systems.
The type of disease that shows up as a result of mitochondrial dysfunction can vary from person to person, even within the same family. It often involves several body systems at once, and symptoms can be intermittent.
Many mitochondrial diseases remain poorly understood, even in the medical community, although awareness and knowledge of the disease is expanding. Genetic testing is one of the most effective ways to help doctors diagnose the disease, and help them with possible treatments.
Genetics of Mitochondrial DisordersThe majority of mitochondrial disorders are caused by defects in nuclear-encoded genes, and follow an autosomal recessive pattern in which there may be history of affected siblings, but (unrelated) parents are asymptomatic or show no signs of illness as gene carriers. Carrier parents have a 1 in 4 or 25% chance in every pregnancy of having a child with mitochondrial disease. It should be noted that some carriers display mild symptoms (Haas, 2007).
A minority of mitochondrial disease cases are associated with mitochondrial or maternal inheritance, in which a mutation in the mitochondrial DNA is potentially passed on from mothers to all offspring. Affected males do not pass on their genetic abnormality in their mitochondrial DNA. The phenotypic or symptom severity in affected individuals can be very broad, even within the same family.
Making a molecular diagnosis of mitochondrial disease requires the identification of DNA abnormalities (mitochondrial and/or nuclear) that are known to cause disease.
Courtagen mitochondria tests available:
- mtSEEK®: Mitochondrial Genome Sequencing and Heteroplasmy Analysis(37 genes of the mtDNA)
- nucSEEK®: Comprehensive Sequence Analysis of the Nuclear Mitochondrial Exome (1,207 genes)
- nucSEEK® Focus: Nuclear Mitochondrial Gene Panel (118 genes)
Medical Comorbidities and Mitochondrial Dysfunction
There are multiple medical conditions and clinical problems that can be affected by mitochondrial dysfunction. Examples include, but are not limited to: developmental delays, autism spectrum disorders, seizures, migraines, chronic fatigue, complex regional pain syndrome, and autonomic (involuntary nervous system) dysfunction (including cyclic vomiting syndrome and heart muscle disease).
Mitochondrial Dysfunction Affects Multiple Systems of the Body
- More than two organ systems are involved
- Two or more episodic neurological manifestations are observed over time