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Natural History Study of Patients With Succinic Semialdehyde Dehydrogenase (SSADH) Deficiency

Who can join

All ages · All sexes

Inclusion Criteria:

* 4-hydroxybutyric aciduria (γ-hydroxybutyric aciduria)
* documented pathogenic ALDH5A1 (aldehyde dehydrogenase 5A1 gene) mutation
* 0-99 years

Exclusion Criteria:

* active or recent substance abuse or dependence within the past year.
* inability to participate in the study procedures.
* any condition that makes the study subject, in the opinion of the investigator, unsuitable for the study.
* patients will be excluded from the MRI section of the study if they have: implanted cardiac pacemaker or autodefibrillators, implanted neural pacemakers, cochlear implants, metallic foreign bodies in the eye or Central Nervous System (CNS), any implanted wire or metal device that may concentrate radio frequency fields.
* patients less than age two years will be excluded from the TMS procedure.

About the study

Succinic Semialdehyde Dehydrogenase deficiency (SSADHD) is a rare autosomal recessive disease that interferes with the catabolism of the major inhibitory neurotransmitter gamma-amino butyric acid (GABA) and furthermore leads to accumulation of various potential toxic metabolites, most prominently gamma hydroxybutyric acid (GHB). Current research indicates that there is developmental delay and significant neurophysiological and biochemical alterations in SSADHD patients, but whether disease presentation varies with age is not known. The investigators propose to determine the natural course of the clinical presentation of SSADHD; to determine the natural course of neurophysiological and biochemical indices known to be altered in SSADHD; and to identify neurophysiological and biochemical predictors of clinical severity.

The overall objective is to define the natural course of the clinical, neurophysiological and biochemical spectrum of SSADHD. Secondary objectives include the identification of biomarkers that correlate with disease phenotype and predict clinical outcomes, and the creation of an international SSADHD data repository for future investigation of pathogenesis and therapy.

What is being tested

• Transcranial magnetic stimulation (TMS) (device)
• Magnetic resonance imaging (MRI) (device)
• Electroencephalogram (EEG) (device)
• Bio-specimen Collection (procedure)

Sponsor: Boston Children's Hospital · Participants: 55 · Started: Jan 15, 2019

Contact the study team

• Melissa L DiBacco, MD · Phone: 617-919-4617

Official record on ClinicalTrials.gov — NCT03758521

Locations in the U.S.

From ClinicalTrials.gov, data retrieved Oct 1, 2026. Each study sets its own eligibility; the study team decides who can join.