Leigh's disease, also known as Subacute Necrotizing Encephalomyelopathy (SNEM), is a rare neurometabolic disorder that affects the central nervous system.

Causes

It is an inherited disorder that usually affects infants between the age of three months and two years, but, in rare cases, teenagers and adults as well. In the case of the disease, mutations in mitochondrial DNA (mtDNA) or in nuclear DNA (gene SURF1^[1] and some COX assembly factors) cause degradation of motor skills and eventually death.

Mitochondria are some of the most important organelles in animal cells as they provide energy for the cell's function. In humans, their primary function is to convert the potential energy of glucose, amino acids, and fatty acids into that of adenosine triphosphate (ATP). Mitochondria are also unique in that they carry their own type of DNA, mitochondrial DNA [mtDNA]. The information stored in the mtDNA is used in the creation of new mitochondria.

When improper mutations of the mtDNA cause the mitochondria to fail to function properly, a person is at risk for number of disorders, including Leigh's disease. In the case of Leigh's disease, crucial cells in the brain stem have mutated mtDNA, creating poorly functioning mitochondria. This causes a chronic lack of energy in the cells, which, in turn, affects the central nervous system and inhibits one's motor skills.

Signs and Symptoms

The disease is most noted for its degradation in one's ability to control one's movements. As it progresses rapidly, the earliest signs may be poor sucking ability and loss of head control and motor skills. Other symptoms include loss of appetite, vomiting, irritability, continuous crying (in infants), and seizures. A later sign can also be episodes of lactic acidosis, which can lead to impairment of respiratory and kidney function. Some children can present with loss of development skills or developmental regression and have often had investigations for failure to thrive. As the disease progresses in adults, it may also cause general weakness, kidney failure, and heart problems. Life expectancy is usually about a year within the onset of symptoms although both acute fulminating illness of a few days and prolonged survival have been reported.

Treatment

Leigh's disease is a very rare disorder, and there is currently no cure. It usually affects infants under two years of age, but, in rarer cases, teenagers and adults as well. A high-fat, low-carbohydrate diet may be recommended. Adults may have puffiness and/or swelling of the eye area and the hands. It is currently treated with thiamin (vitamin B₁), but even with treatment, infants rarely live longer than two or three years after the onset of the disease. In cases of older people, the disease takes longer, but is still almost always fatal.

X-linked Leigh's disease

There is another form of this disease called the X-linked Leigh's syndrome (OMIM 308930), which is a mutation in the oxidative phosphorylation enzymes (which are both on the mtDNA and the nuclear DNA). The X-linked Leigh's disease is a mutation of a gene encoding PDHA1, part of the pyruvate dehydrogenase complex, located on the X chromosome.^[2]

References

External links

• The Children's Rare Disease Network

de:Leigh-Syndrom es:Síndrome de Leigh nl:Syndroom van Leigh pl:Zespó? Leigha pt:Síndrome de Leigh ru:??????? ???

---

Source: Wikipedia | The above article is available under the GNU FDL. | Edit this article