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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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