Mitochondria are present in the cells that are responsible for the production of around 90% of the energy required by the body. They function to process the oxygen and to convert the food that we consume into energy. Mitochondrial diseases are often inherited genetic conditions that develop when the mitochondria do not produce sufficient quantity of energy required for the normal function of the body. This disease can affect any part of the body such as the cells of the brain, the kidneys, nerves, liver, eyes and the pancreas. It can be evident at the birth of the infant or can occur at any age. Some of the causes of secondary mitochondrial dysfunction include muscular dystrophy, Parkinson’s disease, cancer and autism.
Causes
In most cases, this is an inherited condition that is passed from the parents to their children. Individuals normally inherit two pairs of genes; one from the mother and the other from the father. Among the individuals with this disease, the affected individual does not inherit the healthy pair of genes from the parents. This is because the healthy gene has mutated meaning it has become defective. Mitochondrial diseases can be inherited either in an autosomal recessive manner, autosomal dominant pattern or mitochondrial inheritance. Autosomal recessive mode of inheritance means the affected child receives a single copy of the mutated gene from each parent. The autosomal dominant pattern of inheritance means the child receives a single copy of the mutated gene from either parent. The mitochondrial inheritance is exclusively inherited from the mother which is the result of mutations in the mitochondrial DNA. In some cases, a random genetic mutation occurs with no history of the condition present in the family.
Symptoms
Mitochondrial diseases can affect organs such as the brain, muscle and the heart. The symptoms associated with this condition are based on the cells of the body that is affected and can occur at any age. The symptoms can include poor growth, loss of muscle coordination, mental retardation, developmental delays, hearing problems, muscle weakness, diabetes, thyroid dysfunction, respiratory problems, neurological problems and dementia. Children affected with this condition can become lethargic presenting difficulties with concentration that are related to the exhaustion within the cellular level.
Diagnosis
The diagnosis of the mitochondrial disease can be difficult because of the several organs that can be affected. The initial diagnostic method involves various examination such as a complete physical examination, a neurological examination and metabolic examination consisting of blood or urine tests. Additional specialized tests include MRI or MRS for neurological symptoms, retinal examination for vision problems, EKG for heart conditions, audiogram for hearing symptoms and blood tests. Molecular genetic testing can help determine the cause by identifying the mutation that is causing this condition.
Treatment
There is no cure this type of diseases and the treatment focuses on providing relief from the symptoms. The treatment is also based on the symptoms that are evident in each case and its severity. Some of the treatments include vitamin supplements, medications and exercises to increase muscle strength. Depending on the severity of the condition treatments can also include respiratory therapy, occupational therapy and speech therapy.
References
https://my.clevelandclinic.org/health/articles/what-are-mitochondrial-diseases
http://mitochondrialdiseases.org/mitochondrial-disease/
https://rarediseases.info.nih.gov/diseases/7048/mitochondrial-genetic-disorders
http://www.thelilyfoundation.org.uk/mi/mitochondrial-disease/