Mitochondrial Myopathy

Mitochondrial Myopathy Definition

It is a type of a disorder of a muscle tissue or a muscle that is related with mitochondrial disease. Mitochondrial myopathies are a group of neuro-muscular diseases which occur due to the damage of mitochondria or small energy producing structures in the cells. These are the power plants that provide energy to both the muscle and brain. The nerve cells in the brain and muscles require a lot of energy and thus, appear to get damaged when mitochondrial dysfunction occurs. The inheritance of this condition is maternal.

Mitochondrial Myopathy Symptoms

The symptoms of the disorder include:

  • Lactic acidosis
  • Hearing loss
  • Weight loss
  • Strokes
  • Varying types of dementia
  • Short stature
  • Progressive myoclonic epilepsy
  • External opthalmolegia
  • Progressive opthalmoparesis
  • Cardiac conduction effects
  • Clump formations of diseased mitochondria accumulate in muscle fibers. They appear as “ragged-red fibers” when muscle is stained
  • Droopy eyelids
  • Vomiting

Mitochondrial Myopathy Causes

The disorder is mainly caused due to mutations in the mitochondrial DNA or in the nuclear genes. It may be acquired or inherited. They may also occur due to mitochondrial dysfunction caused due to adverse effects from drugs, environmental and infections.

During cell division, the mitochondrial DNA copies separate randomly between the two new mitochondria obtained from the father and mother and make more copies. Mitochondrial disease will become clinically apparent once the number of affected mitochondria inherited from the mother rises to a certain level. Mitochondrial DNA disorders may occur spontaneously and more frequently as the mtDNA lacks the error checking capability. Defects in enzymes that control mitochondrial DNA replication may also cause mitochondrial DNA mutations.

Most of the mitochondrial function and biogenesis is controlled by nuclear DNA. Faults in nuclear-encoded mitochondrial genes are related to hundreds of clinical disease phenotypes, including:

  • Anemia
  • Retinopathy
  • Seizures
  • Lymphoma
  • Hypertension
  • Dementia

Mitochondrial Myopathy Diagnosis

The diagnosis of this disorder involves clinical observation at the initial stage. At a later stage, a doctor opts for laboratory tests and genetic analysis. The physician carefully studies the family medical history of the patient before deciding on the next step for diagnosis.

The diagnostic criteria for this condition involve:

  • Phenotype evaluation or observing symptoms.
  • Muscle biopsy or removal of a small piece of muscle to find abnormal levels of certain enzymes and other substances.
  • Lumbar puncture, for evaluating the fluid that surrounds the spinal cord and the brain.
  • A blood test is done to observe abnormal levels of enzymes and the presence of proteins.
  • A genetic test of the blood and muscle biopsy is carried out in the laboratory to find out the mutated genes.

Mitochondrial Myopathy Treatment

There is no cure for this disease. Its treatment is solely aimed at relieving pain and other symptoms and maximizing the level of movement. Treatment for individuals affected by the disease is best conducted by a neurologist or a genetic specialist who has experience in treating, managing and diagnosing sufferers of the disorder.

The options available for curing the disease include:

Physical therapy

Therapies may be carried out to strengthen muscle and improve movements. Some patients might require walkers, braces and wheel chairs to support their movements.

Respiration Therapy

In this therapy, pressurized air treatment or the use of a ventilator is opted for.

Speech Therapy

For patients who have problem in speaking clearly due to the disease would require speech therapy.

Dietary Supplements

Supplements may help build energy in the cells. They are Creatine, Coenzyme Q10, Carnitine, lipoic acid, Riboflavin, Vitamin K or Idebenone. These antioxidants can minimize the damage caused by free radicals.

Medications

Medications are used to cure specific symptoms like seizures and pain.

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