Cytochrome C Oxidase Deficiency

Important
It is possible that the main title of the report Cytochrome C Oxidase Deficiency 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

COX Deficiency
Deficiency of Mitochondrial Respiratory Chain Complex IV
Complex IV Deficiency

Disorder Subdivisions

COX Def., Infantile Mitochondrial Myopathy, de To ni-Fanconi-Debre included
Leigh's Syndrome (Subacute Necrotizing Encephalomyelopathy)
COX Deficiency French-Canadian Type
COX Deficiency Type Benign Infantile Mitochondrial Myopathy

General Discussion

Cytochrome C Oxidase Deficiency is a very rare inherited metabolic disorder characterized by deficiency of the enzyme cytochrome C oxidase (COX), or Complex IV, an essential enzyme that is active in the subcellular structures that help to regulate energy production (mitochondria). Deficiency of COX may be limited (localized) to the tissues of the skeletal muscles or may affect several tissues, such as the heart, kidney, liver, brain, and/or connective tissue (fibroblasts); in other cases, the COX deficiency may be generalized (systemic).

Four distinct forms of Cytochrome C Oxidase Deficiency have been identifed. The first form of this disorder is known as COX Deficiency Type Benign Infantile Mitochondrial Myopathy. Affected infants exhibit many of the same symptoms as those with the more severe infantile form of the disease; however, because the COX deficiency is limited (localized) to tissues of the skeletal muscles, they typically do not have heart or kidney dysfunction.

In the second type of the disease, known as COX Deficiency Type Infantile Mitochondrial Myopathy, because the COX deficiency affects tissues of the skeletal muscles as well as several other tissues, the disorder may be characterized by a generalized weakness of skeletal muscles (myotonia), abnormalities of the heart and kidneys, and/or abnormally high levels of lactic acid in the blood (lactic acidosis).

The third form of COX Deficiency, known as Leigh's Disease (Subacute Necrotizing Encephalomyelopathy), is thought to be a generalized (systemic) form of COX Deficiency. Leigh's Disease is characterized by progressive degeneration of the brain and dysfunction of other organs of the body including the heart, kidneys, muscles, and liver. Symptoms may include loss of previously acquired motor skills, loss of appetite, vomiting, irritability, and/or seizure activity. As Leigh's Disease progresses, symptoms may also include generalized weakness; loss of muscle tone (hypotonia); and/or episodes of lactic acidosis.

In the fourth form of COX Deficiency, known as COX Deficiency French-Canadian Type, the COX deficiency affects tissues of the skeletal muscles, connective tissue, and, in particular, the brain (Leigh's Disease) and the liver. Affected infants and children may demonstrate developmental delays, diminished muscle tone (hypotonia), crossing of the eyes (strabismus), Leigh's Disease, and/or episodes of lactic acidosis.

Many cases of COX Deficiency are inherited as an autosomal recessive genetic trait. However, it is possible that other cases may be inherited due to abnormal changes in genetic material (mutation) found within mitochondria (mtDNA).

Resources

CLIMB (Children Living with Inherited Metabolic Diseases)
Climb Building
176 Nantwich Road
Crewe, Intl CW2 6BG
United Kingdom
Tel: +44 870 7700 325
Fax: +44 870 7700 327
Email: info@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
Email: info@umdf.org
Internet: http://www.umdf.org

Lactic Acidosis Support Trust
1A Whitley Close
Middlewich
Cheshire, CW10 0NQ
United Kingdom
Tel: 0160683719
Fax: 01606837198

NIH/National Institute of Diabetes, Digestive & Kidney Diseases
Endocrine Diseases Metabolic Diseases Branch
2 Information Way
Bethesda, MD 20892-3570
Tel: (301)654-3810
Fax: (301)496-7422
Email: NDDIC@info.niddk.nih.gov
Internet: http://www.niddk.nih.gov

MUMS (Mothers United for Moral Support, Inc) National Parent-to-Parent Network
150 Custer Court
Green Bay, WI 54301-1243
USA
Tel: (920)336-5333
Fax: (920)339-0995
Tel: (877)336-5333
Email: mums@netnet.net
Internet: http://www.netnet.net/mums/

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html

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: 1/15/2009
Copyright 1997, 1998, 1999, 2007 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization of Rare Disorders

Last Updated: January 15, 2009

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