Leigh disease, commonly referred to as Leigh’s disease, is a rare neurometabolic disorder, which is a disorder that prevents cells in the central nervous system from producing energy. The cells are unable to produce energy for growing and maturing because they are unable to convert nutrients from the bloodstream into a form of energy that can be used by the cell as fuel. Since the cells are unable to produce the energy to grow and maintain themselves, energy depletion accumulates, and the cells begin to deteriorate and die. Since Leigh disease strikes primarily at the time of maximum growth — from birth to early childhood — and since it affects the brain at a vital period of development, the disease is invariably fatal.
Leigh disease was discovered in the early 1950s by Dr. Denis Leigh, and at that time it was termed a “deadly” disease, due to its prevalence for fatalities among the very young. It is characterized by a rapid failure of the body to develop, along with seizures and loss of coordination. The disease can also occur during the adolescent or early adult years, but when it does so, it is then termed subacute necrotizing encephalomyelopathy (SNEM). The tendency for cellular dysfunction is thought by many medical specialists to be inherited on the maternal side, and it has been found to be linked to mutation of the cellular DNA, the genetic material of a cell that gets passed on to newly created cells.
In neurology, an area of medicine that studies the brain and nervous system, Leigh disease is classified as being one of the most severe forms of known mitochondrial diseases caused by defective cell mitochondria — the part of the cell that produces energy. Other less lethal forms exist, depending upon how the energy production of cells is affected. Smaller groups of cells with abnormal genetic material can exist, producing milder forms of mitochondrial disease, since higher numbers of normal energy-producing cells can mitigate the severity of the disease. Both nerve and muscle cells are particularly subject to mitochondrial disease, due to their high energy requirements, and the condition caused by deteriorating muscle fiber cells is known as mitochondrial myopathy.
Leigh disease is actually a syndrome, in that it affects both the muscles and the brain, and is also called mitochondrial encephalomyopathy. There is no known cure for the disease, and treatment depends upon its severity. Food supplements have been tried in an effort to help replace substances needed by the body that are unable to be produced by the affected cells. Combined forms of natural enzymes and amino acids — such as as creatine, L-carnitine and coQ10 supplements — have been used, and although they have not been shown to make a medical improvement in mitochondrial disease, they are generally believed to be beneficial.