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Maternally Inherited Leigh Syndrome and NARP Syndrome

National Organization for Rare Disorders, Inc.

Important
It is possible that the main title of the report Maternally Inherited Leigh Syndrome and NARP Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Synonyms

  • MILS-NARP syndrome

Disorder Subdivisions

  • neuropathy, ataxia and retinitis pigmentosa (NARP)
  • maternally inherited Leigh syndrome (MILS)
  • mtDNA-associated Leigh syndrome

General Discussion

Summary
Maternally inherited Leigh syndrome (MILS) and neuropathy, ataxia and retinitis pigmentosa (NARP) syndrome are rare genetic multisystem disorders that are part of a spectrum or continuum of disease caused by abnormalities affecting mitochondrial energy production. NARP is characterized by nerve disease affecting the nerves outside of the central nervous system (peripheral neuropathy), an impaired ability to coordinate voluntary movements (ataxia), an eye condition known as retinitis pigmentosa (RP), and a variety of additional abnormalities. MILS is generally a more severe mitochondrial disorder that often becomes apparent during infancy or childhood and is characterized by brain disease (encephalopathy), elevated levels of lactic acid in the body (lactic acidosis), seizures, heart disease (cardiomyopathy), breathing (respiratory) abnormalities, and developmental delays. The specific symptoms and severity of these disorders in each individual can vary greatly from one person to another and even among members of the same family.

MILS and NARP syndrome are maternally inherited mitochondrial disorders. They are caused by specific mutations affecting the mitochondrial gene known as the ATPase 6 gene. When individuals have more than 90 percent of mutated mitochondrial DNA (mtDNA) in their cells, they are classified as having MILS and not NARP syndrome. Most individuals with NARP syndrome have 70-80 percent of mutated mtDNA. In some families, one individual may have NARP syndrome while another individual is diagnosed with MILS. (For more information on mtDNA see the Causes section below.)

Introduction
Mitochondrial disorders are characterized by mutations affecting the parts of the cell that release energy (mitochondria). Mitochondrial diseases often hamper the ability of affected cells to break down food and oxygen and produce energy. In most mitochondrial disorders, abnormally high numbers of defective mitochondria are present in the cells of the body. Mitochondrial diseases often affect more than one organ system of the body. NARP syndrome was first identified in the medical literature in 1990. Leigh syndrome was first reported in the medical literature in 1951.

Resources

CLIMB (Children Living with Inherited Metabolic Diseases)
Climb Building
176 Nantwich Road
Crewe, CW2 6BG
United Kingdom
Tel: 4408452412173
Fax: 4408452412174
Email: enquiries@climb.org.uk
Internet: http://www.CLIMB.org.uk

United Mitochondrial Disease Foundation
8085 Saltsburg Road Suite 201
Pittsburgh, PA 15239
United States
Tel: (412)793-8077
Fax: (412)793-6477
Tel: (888)317-8633
Email: info@umdf.org
Internet: http://www.umdf.org

Retinitis Pigmentosa International
P.O. Box 900
Woodland Hills, CA 91365
Tel: (818)992-0500
Fax: (818)992-3265
Tel: (800)344-4877
Email: info@rpinternational.org
Internet: http://www.rpinternational.org

NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424
TDD: (301)468-5981
Internet: http://www.ninds.nih.gov/

Mitochondrial Disease Support Group Online
5022 Michigan Avenue
West Palm Beach, FL 33415
Tel: (407)641-4712
Email: madmolmom@gmail.com
Internet: http://www.mitosupport.org/

Children's Mitochondrial Disease Network
Mayfield House
30 Heber Walk
Chester Way
Northwich
England, CW9 5JB
United Kingdom
Tel: 440160643946
Fax: 440160643946
Email: info@cmdn.org.uk
Internet: http://www.emdn-mitonet.co.uk/

Mitochondria Research Society
Department of Cancer Genetics
Roswell Park Cancer Institute
BLSC Building, Room # 3-316
Elm and Carlton Streets
Buffalo, NY 14221
Tel: (716)845-8017
Fax: (716)845-1047
Email: keshav@mitoresearch.org
Internet: http://www.mitoresearch.org

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223
Internet: http://rarediseases.info.nih.gov/GARD/

Retina International
Ausstellungsstrasse 36
CH-8005
Zürich,
Switzerland
Tel: 410444441077
Fax: 410444441070
Email: christina.fasser@retina-international.org
Internet: http://www.retina-international.org

MitoAction
14 Pembroke Street
Medford, MA 02155
Tel: (888)648-6228
Fax: (888)648-6228
Email: info@mitoaction.org
Internet: http://www.MitoAction.org

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

Last Updated:  1/31/2013
Copyright  2005, 2013 National Organization for Rare Disorders, Inc.

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