Succinic Semialdehyde Dehydrogenase Deficiency

Content provided by National Organization for Rare Disorders

Important

It is possible that the main title of the report Succinic Semialdehyde Dehydrogenase 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

• 4-Hydroxybutyric Aciduria
• SSADH Deficiency

Disorder Subdivisions

• None

General Discussion

Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare inborn error of metabolism that is inherited as an autosomal recessive trait. In individuals with the disorder, deficient activity of the SSADH enzyme disrupts the metabolism of gamma-aminobutyric acid (GABA). GABA is a natural chemical known as a "neurotransmitter" that serves to inhibit the electrical activities of nerve cells (inhibitory neurotransmitter). SSADH deficiency leads to abnormal accumulation of the compound succinic semialdehyde, which is reduced or converted to 4-hydroxybutyric acid, also known as GHB (gamma-hydroxybutyric acid). GHB is a natural compound that has a wide range of effects within the nervous system. The "hallmark" laboratory finding associated with SSADH deficiency is elevated levels of GHB in the urine (i.e., 4-hydroxybutyric or gamma-hydroxybutyric aciduria), the liquid portion of the blood (plasma), and the fluid that flows through the brain and spinal canal (cerebrospinal fluid [CSF]).



SSADH deficiency leads to various neurological and neuromuscular symptoms and findings. These abnormalities may be extremely variable from case to case, including among affected members of the same families (kindreds). However, most individuals with SSADH deficiency are affected by mild to severe mental retardation, delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation), and delays in language and speech development. In addition, in some cases, initial findings may include diminished muscle tone (hypotonia), an impaired ability to coordinate voluntary movements (ataxia), and/or episodes of uncontrolled electrical activity in the brain (seizures). Some affected individuals may also have additional abnormalities, such as decreased reflex reactions (hyporeflexia); involuntary, rapid, rhythmic eye movements (nystagmus); increased muscular activity (hyperkinesis); and/or behavioral abnormalities.

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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



March of Dimes Birth Defects Foundation

1275 Mamaroneck Avenue

White Plains, NY 10605

Tel: (914)428-7100

Fax: (914)997-4763

Tel: (888)663-4637

Email: Askus@marchofdimes.com

Internet: http://www.marchofdimes.com



The Arc (a national organization on mental retardation)

1010 Wayne Ave

Suite 650

Silver Spring, MD 20910

Tel: (301)565-3842

Fax: (301)565-3843

Tel: (800)433-5255

TDD: (817)277-0553

Email: info@thearc.org

Internet: http://www.thearc.org/



Epilepsy Foundation

4351 Garden City Drive

Landover, MD 20785

Tel: (301)459-3700

Fax: (301)577-2684

Tel: (800)332-1000

TDD: (800)332-2070

Email: postmaster@efa.org

Internet: http://www.epilepsyfoundation.org



NIH/National Institute of Child Health & Human Development (Preg & Perinat)

Pregnancy and Perinatology Branch

6100 Executive Blvd Rm 4B03

Bethesda, MD 20892-7510

Tel: (301)496-5575

Email: BOCKR@mail.nih.gov

Internet: http://www.nichd.nih.gov



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



National Institute of Neurological Disorders and Stroke (NINDS)

31 Center Drive

8A07

Bethesda, MD 20892-2540

Tel: (301)496-5751

Fax: (301)402-2186

Tel: (800)352-9424

Email: braininfo@ninds.nih.gov

Internet: http://www.ninds.nih.gov/



Pediatric Neurotransmitter Disease Association (PND Association)

6 Nathan Drive

Plainview, NY 11803

Tel: (516)937-0049

Fax: (516)937-0049

Email: PND@PNDAssoc.org

Internet: http://www.pndassoc.org

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:  4/25/2008

Copyright  2000, 2002, 2003 National Organization for Rare Disorders, Inc.

Last updated:	April 25, 2008