The Mitochondrial Disease Clinic at Johns Hopkins All Children’s Hospital was established to improve medical care for children with mitochondrial disorders in the region. As a research hospital, we will be contributing to studies that aid in advanced medical care and treatment approaches.
Our mission is to educate patients, families and the community about mitochondrial diseases and to develop innovative approaches and long-term treatment plans specially designed for each patient.
What is Mitochondrial Disease?
Mitochondrial diseases are chronic, genetic disorders that occur when the mitochondria of the cell fails to produce enough energy for cell or organ function. Mitochondria are responsible for processing oxygen and producing energy for essential cell functions. The energy produced is in the form of adenosine triphosphate (ATP), which is then transported to the cytoplasm of a cell for use in numerous cell functions. When one or more steps of these chemical reactions do not happen, there is an energy crisis and the cells cannot function normally. As a result, organ systems that need more energy start to fail. The incompletely burned substances might accumulate as poison such as free radicles inside the cells and damage many organ systems.
Mitochondrial disease is not one disease but actually constitutes a large group of disorders. All are defects in energy metabolism, i.e., the synthesis and/or utilization of energy generated as ATP through oxidative phosphorylation or aerobic metabolism.
Mitochondrial disease patients are among the most complex and challenging patients. The disease is multi-systemic and progressive in its course, although the rate of progression is completely unpredictable. The clinical presentation of the disease is heterogeneous, and each patient's disease follows its own path, even when more than one family member has the disease due to the same underlying cause. The symptoms may vary in their severity due to any number of genetic, physiologic and environmental factors.
What are the Symptoms?
The types of mitochondrial diseases are categorized according to the organ systems affected and symptoms present. Mitochondrial diseases might affect the cells of the brain, nerves (including the nerves to the stomach and intestines), muscles, kidneys, heart, liver, eyes, ears or pancreas. In some patients, only one organ is affected while in other patients, all organs are involved. Depending on how severe the mitochondrial disorder is, the illness can range in severity from mild to fatal.
Depending on which cells of the body are affected, symptoms may include:
- Poor growth
- Loss of muscle coordination, muscle weakness
- Visual and/or hearing problems
- Developmental delays, learning disabilities
- Mental retardation
- Heart, liver or kidney disease
- Gastrointestinal disorders, severe constipation
- Respiratory disorders
- Increased risk of infection
- Neurological problems such as movement disorders and seizures
- Thyroid dysfunction
- Dementia (mental disorder characterized by confusion, disorientation and memory loss)
Currently Known Diseases with Mitochondrial Dysfunction:
- Leber hereditary optic neuropathy (LHON)
- Mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS)
- Kearns-Sayre syndrome (KSS)
- Progressive external ophthalmoplegia (PEO)
- Neuropathy ataxia retinitis pigmentosia (NARP)
- Myoclonus epilepsy with ragged red fibers (MERRF)
- Leigh syndrome
How are Mitochondrial Diseases Diagnosed?
There is no single laboratory or diagnostic test that confirms a diagnosis of mitochondrial disease. An array of blood tests, including DNA testing, imaging and/or muscle biopsies, are used in diagnosing patients.
How Do We Treat Mitochondrial Disease?
Currently, there are no cures for mitochondrial diseases, but treatment can help reduce symptoms and delay or prevent the progression of the disease. Treatment is individualized for each patient and requires teamwork by many kinds of healthcare providers including neurologist, geneticist, cardiologist, radiologist, anesthesiologist, ophthalmologist and gastro-intestinal specialists. Certain vitamin and enzyme therapies, along with occupational and physical therapy, might be helpful for some patients. Other treatments that might be useful include dietary therapy and anti-oxidants.
Resources / Organizations
United Mitochondrial Disease Foundation (UMDF)
8085 Saltsburg Road Suite 201
Pittsburgh, PA 15239
Phone: 888-317-8633 - Toll free
National Organization for Rare Diseases (NORD)
P.O. Box 1968
55 Kenosia Avenue
Danbury, CT 06813
Phone: 800-999-NORD (6673)