Succinic Semialdehyde Dehydrogenase Deficiency

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.

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