Taurine Therapy for SSADH Deficiency

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01608178
Recruitment Status : Completed
First Posted : May 30, 2012
Last Update Posted : January 10, 2019
Information provided by:
National Institutes of Health Clinical Center (CC)

Brief Summary:


- Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare genetic disease that results in changes to certain brain chemicals. These chemicals may affect brain excitability, or how likely nerve cells are to turn on. Changes in brain excitability may help to explain the symptoms of the disease, including learning and memory problems, seizures, and poor balance. A supplement called taurine may help people with SSADH deficiency by working on the brain chemical GABA. GABA helps to regulate brain activity. Researchers want to see if taurine can help people with SSADH deficiency.


- To learn more about how taurine affects the brain in people with SSADH deficiency.


- Individuals at least 12 years of age who have SSADH deficiency.


  • Participants will be screened with a physical exam and medical history. They will provide blood and urine samples. They will also take taurine supplements as part of this protocol.
  • Participants will have two sets of study tests. One set will be given while participants are taking taurine. The second will be given when they are not taking it. Each testing session will take about 2 days to complete.
  • Half of the participants will have the "off taurine" testing before starting on the taurine supplement. The other half will start taking taurine first, have the "on taurine" testing, and have the "off taurine" testing about 3 months after stopping taurine. Participants may decide the order in which they will have the testing done.
  • Participants will have the following tests at the two test visits:
  • Paper and pencil tests of learning and memory.
  • Transcranial magnetic stimulation to study the excitability of nerve cells.
  • Imaging studies to show GABA receptors in the brain and measure their activity.
  • Electroencephalogram to measure brain waves.
  • Lumbar puncture to collect spinal fluid.
  • Participants will be monitored with regular study visits while they receive the taurine supplement treatment.

Condition or disease
Succinic Semialdehyde Dehydrogenase

Detailed Description:

Objective: To study the physiologic effects of taurine therapy in patients with succinic semialdehyde Dehydrogenase (SSADH) deficiency.

Study Population: Eighteen children and adults with SSADH deficiency receiving taurine.

Design: This small open label trial will evaluate the effect of taurine treatment on key SSADH biomarkers and neurocognitive performance. Study evaluations will include neurological and neuropsychological examinations, positron emission tomography (PET) with 11C-flumazenil (FMZ), (optional and only for those over age 18), magnetic resonance spectroscopy (MRS) (optional) and cerebrospinal fluid (CSF) collection (optional) to measure gamma-aminobutyric acid (GABA) levels, and transcranial magnetic stimulation (TMS) to measure cortical excitation and inhibition, in patients given taurine for SSADH deficiency.

The evaluations will be performed twice, on and off therapy.

Study Type : Observational
Actual Enrollment : 7 participants
Time Perspective: Prospective
Official Title: Succinic Semialdehyde Dehydrogenase Deficiency: Physiological Markers of Taurine Therapy
Study Start Date : April 27, 2012
Study Completion Date : December 16, 2013

Primary Outcome Measures :
  1. TMS parameters of cortical excitation and inhibition.

Secondary Outcome Measures :
  1. Change in CSF GABA, GHB, succinic semialdehyde, homocarnosine, 4,5-dihydroxyhexanoic acid, D-2-hydroxyglutaric acid, homovanillic acid, and 5-HIAA levels.

Information from the National Library of Medicine

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Ages Eligible for Study:   12 Years and older   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Persistent 4-hydroxybutyric aciduria (gamma-hydroxybutyric aciduria).

Documented succinic semialdehyde dehydrogenase enzyme deficiency.

Patients will be at least 12 years old.

Be enrolled in the taurine study at CNMC.


Pregnancy or lactation.

Patients with a history of other significant medical disorders.

Patients requiring treatment with drugs known to affect the GABAergic system, including vigabatrin, barbiturates, and benzodiazepines.

Hearing loss. The effect of TMS on hearing is not fully known. Patients will be screened with an Audiometer.

Abnormal platelets or coagulation studies suggesting increased risk for lumbar puncture or TMS

Exclusions for MRI and MRS: pacemakers or other implanted electrical devices, brain stimulators, some types of dental implants, aneurysm clips (metal clips on the wall of a large artery), metallic prostheses (including metal pins and rods, heart valves, and cochlear implants), permanent eyeliner, implanted delivery pump, or shrapnel fragments, welders and metal workers.

Exclusions for TMS: people with implanted medical devices such as pacemakers, implanted pumps, stimulators, or cochlear implants or in people who have metal objects inside the eye or skull.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01608178

United States, Maryland
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Institute of Neurological Disorders and Stroke (NINDS)
Principal Investigator: William H Theodore, M.D. National Institute of Neurological Disorders and Stroke (NINDS)