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.
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.
March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 Tel: (914)997-4488 Fax: (914)997-4763 Tel: (888)663-4637 Email: Askus@marchofdimes.com Internet: http://www.marchofdimes.com
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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/
11q Research and Resource Group 5155 Shotwell Street Woodstock, GA 30188 USA Tel: (404)428-8440 Email: firstname.lastname@example.org Internet: http://www.11qusa.org
NIH/National Institute of Child Health and Human Development 31 Center Dr Building 31, Room 2A32 MSC2425 Bethesda, MD 20892 Fax: (866)760-5947 Tel: (800)370-2943 TDD: (888)320-6942 Email: NICHDInformationResourceCenter@mail.nih.gov Internet: http://www.nichd.nih.gov/
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/
Madisons Foundation PO Box 241956 Los Angeles, CA 90024 Tel: (310)264-0826 Fax: (310)264-4766 Email: email@example.com Internet: http://www.madisonsfoundation.org
SSADH Association, Inc. 498 Lillian Court P.O. Box 180622 Delafield, WI 53018 USA Tel: (262)646-5133 Fax: (262)255-8218 Email: firstname.lastname@example.org Internet: www.ssadh.net
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Last Updated: 4/25/2008 Copyright 2000, 2002, 2003 National Organization for Rare Disorders, Inc.
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