Succinic Semialdehyde Dehydrogenase Deficiency
National Organization for Rare Disorders, Inc.
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.
CLIMB (Children Living with Inherited Metabolic Diseases)
176 Nantwich Road
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March of Dimes Birth Defects Foundation
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Washington, DC 20006
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NIH/National Institute of Diabetes, Digestive & Kidney Diseases
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NIH/National Institute of Neurological Disorders and Stroke
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NIH/National Institute of Child Health and Human Development
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Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
PO Box 241956
Los Angeles, CA 90024
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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
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Last Updated: 4/25/2008
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