Leigh Syndrome Health Article

Prenatal testing

Genetic counseling may be of benefit for families with a history of Leigh syndrome. Prenatal testing is available to assist in prenatal diagnosis. Prior testing of family members is usually necessary for prenatal testing.

Either chorionic villus sampling (CVS) or amniocentesis may be performed for prenatal testing. CVS is a procedure to obtain chorionic villi tissue for testing. Examination of fetal tissue can reveal information about the changes that lead to Leigh syndrome. Chorionic villus sampling can be performed at 10–12 weeks pregnancy.

Amniocentesis is a procedure that involves inserting a thin needle into the uterus, into the amniotic sac, and withdrawing a small amount of amniotic fluid. DNA can be extracted from the fetal cells contained in the amniotic fluid and tested. Amniocentesis is performed at 15–18 weeks pregnancy.

Tissue obtained from CVS or in amniotic fluid that shows evidence of the genetic abnormalities responsible for Leigh syndrome confirms the diagnostic. Other forms of prenatal testing may be available for Leigh syndrome.

Treatment and management

The most common treatment for the disorder is the prescription of thiamine or vitamin B1. This may result in a temporary improvement of the symptoms and slightly slow the progress of the disease.

Patients lacking the pyruvate dehydrogenase enzyme complex may benefit from a high-fat, low-carbohydrate diet.

To treat lactic acidosis, oral sodium bicarbonate or sodium citrate may also be prescribed. To control severe lactic acidosis, intravenous infusion of tris-hydroxy-methyl aminomethane (THAM) may be beneficial. Both treatments help reduce abnormally high acid levels in the blood and the accumulation of lactic acid in the brain.

If eye problems occur, the individual with Leigh syndrome may benefit from treatment from an ophthalmologist.

Treatment should also include assistance with locating support resources for the family and the individual with Leigh syndrome.

Prognosis

Prognosis for individuals with classical Leigh syndrome is poor. Death usually occurs within a few years, although patients may live to be 6 or 7 years of age. Some patients have survived to the mid-teenage years. Children who survive the first episode of the disease may not fully recover physically and neurologically. In addition, they are likely to face successive bouts of devastating illness that ultimately cause death.

BOOKS

Jorde, L. B., et al., eds. Medical Genetics. 2nd ed. St. Louis: Mosby, 1999.

ORGANIZATIONS

Arc (a National Organization on Mental Retardation). 1010 Wayne Ave., Suite 650, Silver Spring, MD 20910. (800) 433-5255. <http://www.thearclink.org>.

Association for Neuro-Metabolic Disorders. 5223 Brookfield Lane, Sylvania, OH 43560-1809. (419) 885-1497.

Children Living with Inherited Metabolic Diseases. The Quadrangle, Crewe Hall, Weston Rd., Crewe, Cheshire, CW1-6UR. UK 127 025 0221. Fax: 0870-7700-327. <http://www.climb.org.uk>.

Children's Brain Disease Foundation. 350 Parnassus Ave., Suite 900, San Francisco, CA 94117. (415) 566-5402.

Epilepsy Foundation of America. 4351 Garden City Dr., Suite 406, Landover, MD 20785-2267. (301) 459-3700 or (800) 332-1000. <http://www.epilepsyfoundation.org>.

Lactic Acidosis Support Trust. 1A Whitley Close, Middlewich, Cheshire, CW10 0NQ. UK (016) 068-37198.

March of Dimes Birth Defects Foundation. 1275 Mamaroneck Ave., White Plains, NY 10605. (888) 663-4637. resourcecenter@modimes.org. <http://www.modimes.org>.

National Institute of Neurological Disorders and Stroke. 31 Center Drive, MSC 2540, Bldg. 31, Room 8806, Bethesda, MD 20814. (301) 496-5751 or (800) 352-9424. <http://www.ninds.nih.gov>.

National Organization for Rare Disorders (NORD). PO Box 8923, New Fairfield, CT 06812-8923. (203) 746-6518 or (800) 999-6673. Fax: (203) 746-6481. <http://www.rarediseases.org>.

United Mitochondrial Disease Foundation. PO Box 1151, Monroeville, PA 15146-1151. (412) 793-8077. Fax: (412) 793-6477. <http://www.umdf.org>.

WEBSITES

Online Mendelian Inheritance in Man. <http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?db=OMIM>.

Jennifer F. Wilson, MS