Mitochondria Often thought of as the smallest unit of a living organism, a cell is made up of many even smaller parts, each with its own function. Human cells vary in size, but all are quite small. Even... read more are the energy factories of cells and carry some of their own genes. When mitochondria stop working properly, less and less energy is generated within the cells. This may lead to cell injury or even cell death, and body systems, often including the muscles, will not function properly. Mitochondrial myopathies can be inherited through faulty genes within the mitochondria themselves or through genes within the cell nucleus.
Mitochondrial myopathies can cause increasing weakness in one or a few muscle groups, such as the eye muscles (ophthalmoplegia) and often affect many other organs, such as the heart, intestines, or brain. Infants whose muscles are affected are weak and have severely reduced muscle tone (hypotonia, or "floppiness"). Depending on which organs are affected, complications may include deafness or hearing loss Hearing Impairment in Children Hearing loss in newborns most commonly results from cytomegalovirus infection or genetic defects and in older children results from ear infections or earwax. If children do not respond to sounds... read more , seizures Seizures in Children Seizures are a periodic disturbance of the brain’s electrical activity, resulting in some degree of temporary brain dysfunction. When older infants or young children have seizures, they often... read more , or stroke-like episodes Overview of Stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply (cerebral infarction) and symptoms that... read more . One mitochondrial myopathy is called Kearns-Sayre syndrome. It causes problems with the eyes, muscles, and heart.
(See also Mitochondrial Disorders Mitochondrial Disorders Mitochondrial disorders are a group of hereditary metabolic disorders that occur when mitochondria do not function correctly in the body. Hereditary disorders occur when parents pass the defective... read more .)
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Muscular Dystrophy Association: Information on research, treatment, technology, and support for people living with a mitochondrial myopathy