Leigh's disease is a rare inherited neurometabolic disorder that affects the central nervous system. This progressive disorder begins in infants between the ages of three months and two years. Rarely, it occurs in teenagers and adults. Leigh's disease can be caused by mutations in mitochondrial DNA or by deficiencies of an enzyme called pyruvate dehydrogenase. Symptoms of Leigh's disease usually progress rapidly. The earliest signs may be poor sucking ability,and the loss of head control and motor skills.These symptoms may be accompanied by loss of appetite, vomiting, irritability, continuous crying, and seizures. As the disorder progresses, symptoms may also include generalized weakness, lack of muscle tone, and episodes of lactic acidosis, which can lead to impairment of respiratory and kidney function.In Leigh’s disease, genetic mutations in mitochondrial DNA interfere with the energy sources that run cells in an area of the brain that plays a role in motor movements. The primary function of mitochondria is to convert the energy in glucose and fatty acids into a substance called adenosine triphosphate ( ATP). The energy in ATP drives virtually all of a cell's metabolic functions. Genetic mutations in mitochondrial DNA, therefore, result in a chronic lack of energy in these cells, which in turn affects the central nervous system and causes progressive degeneration of motor functions.There is also a form of Leigh’s disease (called X-linked Leigh's disease) which is the result of mutations in a gene that produces another group of substances that are important for cell metabolism. This gene is only found on the X chromosome.  The most common treatment for Leigh's disease is thiamine or Vitamin B1. Oral sodium bicarbonate or sodium citrate may also be prescribed to manage lactic acidosis. Researchers are currently testing dichloroacetate to establish its effectiveness in treating  lactic acidosis. In individuals who have the X-linked form of Leigh’s disease, a high-fat, low-carbohydrate diet may be recommended. The prognosis for individuals with Leigh's disease is poor. Individuals who lack mitochondrial complex IV activity and those with pyruvate dehydrogenase deficiency tend to have the worst prognosis and die within a few years. Those with partial deficiencies have a better prognosis, and may live to be 6 or 7 years of age. Some have survived to their mid-teenage years. The NINDS supports and encourages a broad range of basic and clinical research on neurogenetic disorders such as Leigh's disease. The goal of this research is to understand what causes these disorders and then to apply these findings to new ways to diagnose, treat, and prevent them. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&term=leigh+disease+AND+human[mh]+AND+english[la]&db=PubMed&orig_db=PubMed&filters=on&pmfilter_EDatLimit=5+Years 1 http://clinicaltrials.gov/ct2/results?term= /disorders/leighsdisease/pubs_leighsdisease.htm /disorders/leighsdisease/xml_leighsdisease.xml xml_leighsdisease.xml V64 Epilepsy Foundation

8301 Professional Place

Landover MD 20785-7223 postmaster@efa.org http://www.epilepsyfoundation.org 301-459-3700 800-EFA-1000 (332-1000) 301-577-2684 National charitable organization dedicated to the welfare of people with epilepsy. Works to ensure that people with seizures are able to participate in all life experiences; to improve how people with epilepsy are perceived, accepted and valued in society; and to promote research for a cure. Offers a Legal Defense Program through a fund. V91 National Organization for Rare Disorders (NORD)

55 Kenosia Avenue

Danbury CT 06810 orphan@rarediseases.org http://www.rarediseases.org 203-744-0100 Voice Mail 800-999-NORD (6673) 203-798-2291 Federation of voluntary health organizations dedicated to helping people with rare "orphan" diseases and assisting the organizations that serve them. Committed to the identification, treatment, and cure of rare disorders through programs of education, advocacy, research, and service. V254 United Mitochondrial Disease Foundation

8085 Saltsburg Road

Suite 201 Pittsburgh PA 15239 info@umdf.org http://www.umdf.org 412-793-8077 888-317-UMDF (8633) 412-793-6477 Promotes research for cures and treatments of mitochondrial disorders and provides support for affected families. Represents adults and children alike and continues to serve families with a variety of programs. V1013 MitoAction

P.O. Box 51474

Boston MA 02205 info@mitoaction.org http://www.mitoaction.org 1-888-648-6228 Works to improve quality of life for adults and children affected by mitochondrial disease and to raise awareness about mitochondrial disorders and their relationship to other diseases.