Succinic Semialdehyde Dehydrogenase DeficiencyNCT03758521
Natural History Study of Patients With Succinic Semialdehyde Dehydrogenase (SSADH) Deficiency
An observational study of Succinic Semialdehyde Dehydrogenase Deficiency, run by Boston Children's Hospital at 4 sites in 4 countries.
Trial summary
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… Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Succinic Semialdehyde Dehydrogenase Deficiency
- What is being tested?
- Transcranial magnetic stimulation (TMS), Magnetic resonance imaging (MRI) and Electroencephalogram (EEG)
- Type of treatment
- Medical device, Surgery or procedure
- How many people
- 55 participants
- Where
- 4 sitesin 4 countries
- Study dates
- 15 Jan 2019to Jun 2029
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Children and adults diagnosed with Succinic Semialdehyde Dehydrogenase (SSADH) deficiency.
Who may be able to join
- 4-hydroxybutyric aciduria (γ-hydroxybutyric aciduria)
- documented pathogenic ALDH5A1 (aldehyde dehydrogenase 5A1 gene) mutation
- 0-99 years
Who cannot join
- 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.
Trial locations and contacts
4 sites in 4 countries. Contact the study team or a site near you to ask about taking part.
4 sites in 4 countries
United States1 site, 1 recruiting
- Recruiting
Boston Children's Hospital
Boston, Massachusetts, 02115
Melissa L DiBacco, MD, 6179194617, melissa.dibacco@childrens.harvard.edu
Phillip L Pearl, MD
Germany1 site, 1 recruiting
- Recruiting
University Children's Hospital
Heidelberg, Heidelberg
Kathrin Jeltsch, MD, Kathrin.Jeltsch@med.uni-heidelberg.de
Thomas Opladen, MD
United Kingdom1 site, 1 recruiting
- Not yet recruiting
Birmingham Children's Hospital NHS Foundation Trust
Birmingham
Allie Berry, alison.berry1@nhs.net
Evangeline Wassmer
About this 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.
Read the detailed description
The study will be conducted by 4 academic institutions: Washington State University (WSU), Boston Children's Hospital (BCH), University of South Florida (USF), and University Children's Hospital Heidelberg (iNTD). The design of the study is mixed, with longitudinal and cross-sectional assessments over a period of 5 years.
Patients will be separated into three cohorts. The Boston Children's cohort will be a total of 20 patients evaluated at Boston Children's Hospital in the United States. These patients will be followed for five years, and attend a visit to the hospital in years 1,3 and 5 where assessments including history/physical, neuropsychological testing, EEG, TMS, and bio-specimen collection will be completed. Each patient will have an MRI of the brain done with special GABA sequencing one time over the five years. Each visit will take place over the course of two days. At BCH, the goal will be to schedule visits every other year with questionnaires and surveys sent out up to every 6 months, and bio-specimen collection every year. The BCH team will also ask for two follow up phone calls occurring 12 months after each onsite visit. Visits will consist of clinical assessments (demographics, medical history, physical examination, neurological exam, medication history, neuropsychological assessments, and clinical severity score), neurophysiological assessments (Brain MRI/MRS/DTI, Electroencephalogram, and Transcranial magnetic stimulation), and yearly bio-specimen collection (blood, urine, saliva, hair, stool, and skin biopsy). Bio-specimens will be sent to Washington State University for testing and addition to a biorepository. The iNTD (international NeuroTransmitters Disorders) cohort will be comprised of 15 patients who are seen at European sites who will have approval through their ethics committee to share de-identified information. Bio-specimens will be attempted to be collected at each visit from patients and sent to Washington State University. At the iNTD sites and for patients followed outside of iNTD, visits and bio-specimen collections will depend on the patients' follow-up schedules with electronic, web-based survey sent on a regular schedule (every 6 months). The standard of care cohort will be comprised of 10 patients throughout the world who provide consent to share de-identified information to the database.
The data will be stored in a database on the University of South Florida server. The server is password protected, and each member of the study personal will have a unique log in to have access to the site. Subjects will also be given specialized access to complete follow up electronic web based surveys twice a year over the course of 5 years. The team at USF will assist with data analysis.
- Being tested
- Transcranial magnetic stimulation (TMS), Magnetic resonance imaging (MRI), Electroencephalogram (EEG), Bio-specimen Collection
- Keywords
- SSADHD, SSADH deficiency
- Medical subject headings
- succinic semialdehyde dehydrogenase deficiency
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Transcranial magnetic stimulation (TMS)Device
Also called Nexstim Navigated Brain Stimulation (NBS) System 4
Transcranial magnetic stimulation (TMS) is a method for noninvasive electrical cortical stimulation, where small intracranial currents are generated by a powerful, fluctuating, extracranial magnetic field. TMS is unique in its capacity for experimental, diagnostic, and therapeutic utility. Single pulse (spTMS) and paired-pulse TMS (ppTMS) have been used extensively to study, measure, and modulate cortical excitability and plasticity.
Magnetic resonance imaging (MRI)Device
These will be outpatient MRI studies that are planned without sedation. Subjects enrolled at BCH will undergo brain MRI, including volumetric MRI, MRS, and diffusion tensor imaging (DTI). The data will help define the natural history of brain volume, brain myelination and spectroscopic (e.g. GABA) abnormalities.
Electroencephalogram (EEG)Device
Also called Natus
These will be outpatient EEG recordings that span 20-60 minutes and done without sedation. Recordings will be performed using electrode locations specified by the international 10-20 system for standard clinical practice.
Bio-specimen CollectionProcedure or surgery
Bio-specimen collection will include blood, urine, saliva, hair, stool, and a skin biopsy. Blood, urine, saliva, blood spots, and hair samples will also be banked for to-be-determined (TBD) studies.
| Study group | Role | What they receive |
|---|---|---|
| BCH Cohort | Patients enrolled at BCH will travel to BCH every 2 years at a minimum for comprehensive evaluation taking place over a 48 hour period. Visits to BCH may occur within ± 2 months of the scheduled visit date. Electronic surveys will be sent out every 6 months.Visits will consist of clinical assessments (demographics, medical history, physical examination, neurological exam, medication history, neuropsychological assessments, and clinical severity score), neurophysiological assessments (Brain Magnetic resonance imaging [MRI/MRS/DTI], Electroencephalogram [EEG], and Transcranial magnetic stimulation [TMS]), and yearly bio-specimen collection. Receives: Device: Transcranial magnetic stimulation (TMS); Device: Magnetic resonance imaging (MRI); Device: Electroencephalogram (EEG); Procedure: Bio-specimen Collection | |
| iNTD Cohort | Patients enrolled at iNTD sites will travel to their iNTD site according to standard of care requirements. Data collection includes clinical history and relevant laboratory-chemical, therapeutic, instrumental and neuropsychological parameters by the study centers. Data collection takes place within the framework of elective outpatient visits. The collected parameters are congruent with the current standard investigations. Electronic surveys will be sent out every 6 months. Imaging and neurophysiological data will be collected if performed during the clinical visit or if performed as part of the site's ongoing research. Yearly bio-specimen collection will be attempted after consent is obtained from the family. Receives: Procedure: Bio-specimen Collection | |
| Standard of Care Cohort | Patients enrolled at other sites will attend their visit at their regular clinical site as mandated by standard of care. Data collection includes medical history, family history, medications, and all clinical and neuropsychological assessments listed. Imaging and neurophysiological data will be collected if performed during the clinical visit or if performed as part of the clinical site's ongoing research. Yearly bio-specimen collection will be attempted. Receives: Procedure: Bio-specimen Collection |
What is being measured
The primary outcome is the main question the study is designed to answer.
Clinical Severity Score
A composite score ranging from 5 (profound impairment) to 25 (no impairment) will be calculated using scores from five clinically significant subdomains (cognition, communication, motor skills, psychiatric presentation, and epilepsy), each scored from 1 (worse) to 5 (no impairment).
Measured: 5 Years
Biochemical - GABA measurement
GABA is measured by electron-capture negative-ion mass fragmentography. The level will be measured in the different bio-specimens.
Measured: 5 Years
Biochemical - GHB measurement
GHB is measured using gas chromatography-mass spectrometry (GCMS). GHB will be measured in the different bio-specimens.
Measured: 5 Years
Quantification of GABA related signals on the MRI spectroscopy
MRI spectroscopy with special editing for GABA-related peaks in multi-voxel MRS. Concentrations will be analyzed.
Measured: 5 Years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Nov 2018
- Study start15 Jan 2019
- Primary completion31 May 2029 (estimated)
- Study completionJun 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Succinic Semialdehyde Dehydrogenase DeficiencyStudies of the same condition, open and under way.
- More trials run by Boston Children's HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 55 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Boston Children's Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Washington State University, University of South Florida, University Hospital Heidelberg, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
- Responsible party
- Principal investigator, Phillip Pearl, Boston Children's Hospital
- Investigators
- Phillip L Pearl, MD, Study chair, Boston Children's Hospital/Harvard Medical SchoolK. Michael Gibson, PhD, Study chair, Washington State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03758521
- Sponsor's protocol ID
- IRB-P00029917
- Other IDs
- 1R01HD091142-01A1
- Status last verified
- Jan 2026
- First submitted
- 16 Nov 2018
- Last updated
- 13 Jan 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Tokatly Latzer I, Lee HHC, Yang E, Alves C, Bertoldi M, Fung C, Steele SV, Kule E, Jin Z, Rotenberg A, Roullet JB, Pearl PL. Central Dysmyelination in SSADH-Deficient Humans and Mice. Ann Clin Transl Neurol. 2025 Nov;12(11):2193-2205. doi: 10.1002/acn3.70148. Epub 2025 Jul 31.
PubMed 40741980Tokatly Latzer I, Roullet JB, Afshar-Saber W, Lee HHC, Bertoldi M, McGinty GE, DiBacco ML, Arning E, Tsuboyama M, Rotenberg A, Opladen T, Jeltsch K, Garcia-Cazorla A, Julia-Palacios N, Gibson KM, Sahin M, Pearl PL. Clinical and molecular outcomes from the 5-Year natural history study of SSADH Deficiency, a model metabolic neurodevelopmental disorder. J Neurodev Disord. 2024 Apr 24;16(1):21. doi: 10.1186/s11689-024-09538-9.
PubMed 38658850
Study at a glance
From the registry record, last updated by the sponsor on 13 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Natural History Study of Patients With Succinic Semialdehyde Dehydrogenase (SSADH) Deficiency
- ClinicalTrials.gov ID
- NCT03758521
- Acronym / sponsor ID
- IRB-P00029917
- Keywords
- SSADHD, SSADH deficiency
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 55 participants (estimated)
- Lead sponsor
- Boston Children's HospitalUniversity, hospital or other
- Collaborators
- Washington State University, University of South Florida, University Hospital Heidelberg, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
- Study start
- 15 Jan 2019 (actual)
- Primary completion
- 31 May 2029 (estimated)
- Study completion
- Jun 2029 (estimated)
- First posted
- 29 Nov 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
The study will be conducted by 4 academic institutions: Washington State University (WSU), Boston Children's Hospital (BCH), University of South Florida (USF), and University Children's Hospital Heidelberg (iNTD). The design of the study is mixed, with longitudinal and cross-sectional assessments over a period of 5 years.
Patients will be separated into three cohorts. The Boston Children's cohort will be a total of 20 patients evaluated at Boston Children's Hospital in the United States. These patients will be followed for five years, and attend a visit to the hospital in years 1,3 and 5 where assessments including history/physical, neuropsychological testing, EEG, TMS, and bio-specimen collection will be completed. Each patient will have an MRI of the brain done with special GABA sequencing one time over the five years. Each visit will take place over the course of two days. At BCH, the goal will be to schedule visits every other year with questionnaires and surveys sent out up to every 6 months, and bio-specimen collection every year. The BCH team will also ask for two follow up phone calls occurring 12 months after each onsite visit. Visits will consist of clinical assessments (demographics, medical history, physical examination, neurological exam, medication history, neuropsychological assessments, and clinical severity score), neurophysiological assessments (Brain MRI/MRS/DTI, Electroencephalogram, and Transcranial magnetic stimulation), and yearly bio-specimen collection (blood, urine, saliva, hair, stool, and skin biopsy). Bio-specimens will be sent to Washington State University for testing and addition to a biorepository. The iNTD (international NeuroTransmitters Disorders) cohort will be comprised of 15 patients who are seen at European sites who will have approval through their ethics committee to share de-identified information. Bio-specimens will be attempted to be collected at each visit from patients and sent to Washington State University. At the iNTD sites and for patients followed outside of iNTD, visits and bio-specimen collections will depend on the patients' follow-up schedules with electronic, web-based survey sent on a regular schedule (every 6 months). The standard of care cohort will be comprised of 10 patients throughout the world who provide consent to share de-identified information to the database.
The data will be stored in a database on the University of South Florida server. The server is password protected, and each member of the study personal will have a unique log in to have access to the site. Subjects will also be given specialized access to complete follow up electronic web based surveys twice a year over the course of 5 years. The team at USF will assist with data analysis.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| BCH Cohort | – | Device: Transcranial magnetic stimulation (TMS), Device: Magnetic resonance imaging (MRI), Device: Electroencephalogram (EEG), Procedure: Bio-specimen CollectionPatients enrolled at BCH will travel to BCH every 2 years at a minimum for comprehensive evaluation taking place over a 48 hour period. Visits to BCH may occur within ± 2 months of the scheduled visit date. Electronic surveys will be sent out every 6 months.Visits will consist of clinical assessments (demographics, medical history, physical examination, neurological exam, medication history, neuropsychological assessments, and clinical severity score), neurophysiological assessments (Brain Magnetic resonance imaging [MRI/MRS/DTI], Electroencephalogram [EEG], and Transcranial magnetic stimulation [TMS]), and yearly bio-specimen collection. |
| iNTD Cohort | – | Procedure: Bio-specimen CollectionPatients enrolled at iNTD sites will travel to their iNTD site according to standard of care requirements. Data collection includes clinical history and relevant laboratory-chemical, therapeutic, instrumental and neuropsychological parameters by the study centers. Data collection takes place within the framework of elective outpatient visits. The collected parameters are congruent with the current standard investigations. Electronic surveys will be sent out every 6 months. Imaging and neurophysiological data will be collected if performed during the clinical visit or if performed as part of the site's ongoing research. Yearly bio-specimen collection will be attempted after consent is obtained from the family. |
| Standard of Care Cohort | – | Procedure: Bio-specimen CollectionPatients enrolled at other sites will attend their visit at their regular clinical site as mandated by standard of care. Data collection includes medical history, family history, medications, and all clinical and neuropsychological assessments listed. Imaging and neurophysiological data will be collected if performed during the clinical visit or if performed as part of the clinical site's ongoing research. Yearly bio-specimen collection will be attempted. |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Children and adults diagnosed with Succinic Semialdehyde Dehydrogenase (SSADH) deficiency.
Key inclusion criteria (3 listed)
- 4-hydroxybutyric aciduria (γ-hydroxybutyric aciduria)
- documented pathogenic ALDH5A1 (aldehyde dehydrogenase 5A1 gene) mutation
- 0-99 years
Key exclusion criteria (5 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Transcranial magnetic stimulation (TMS)Also: Nexstim Navigated Brain Stimulation (NBS) System 4Transcranial magnetic stimulation (TMS) is a method for noninvasive electrical cortical stimulation, where small intracranial currents are generated by a powerful, fluctuating, extracranial magnetic field. TMS is unique in its capacity for experimental, diagnostic, and therapeutic utility. Single pulse (spTMS) and paired-pulse TMS (ppTMS) have been used extensively to study, measure, and modulate cortical excitability and plasticity. | Device | BCH Cohort |
| Magnetic resonance imaging (MRI)These will be outpatient MRI studies that are planned without sedation. Subjects enrolled at BCH will undergo brain MRI, including volumetric MRI, MRS, and diffusion tensor imaging (DTI). The data will help define the natural history of brain volume, brain myelination and spectroscopic (e.g. GABA) abnormalities. | Device | BCH Cohort |
| Electroencephalogram (EEG)Also: NatusThese will be outpatient EEG recordings that span 20-60 minutes and done without sedation. Recordings will be performed using electrode locations specified by the international 10-20 system for standard clinical practice. | Device | BCH Cohort |
| Bio-specimen CollectionBio-specimen collection will include blood, urine, saliva, hair, stool, and a skin biopsy. Blood, urine, saliva, blood spots, and hair samples will also be banked for to-be-determined (TBD) studies. | Procedure or surgery | BCH Cohort, Standard of Care Cohort, iNTD Cohort |
Primary outcome
Clinical Severity Score
Time frame: 5 Years
A composite score ranging from 5 (profound impairment) to 25 (no impairment) will be calculated using scores from five clinically significant subdomains (cognition, communication, motor skills, psychiatric presentation, and epilepsy), each scored from 1 (worse) to 5 (no impairment).
Biochemical - GABA measurement
Time frame: 5 Years
GABA is measured by electron-capture negative-ion mass fragmentography. The level will be measured in the different bio-specimens.
Biochemical - GHB measurement
Time frame: 5 Years
GHB is measured using gas chromatography-mass spectrometry (GCMS). GHB will be measured in the different bio-specimens.
Quantification of GABA related signals on the MRI spectroscopy
Time frame: 5 Years
MRI spectroscopy with special editing for GABA-related peaks in multi-voxel MRS. Concentrations will be analyzed.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Jan 2026.
- Derived from this study: PubMed 40741980Tokatly Latzer I, Lee HHC, Yang E, Alves C, Bertoldi M, Fung C, Steele SV, Kule E, Jin Z, Rotenberg A, Roullet JB, Pearl PL. Central Dysmyelination in SSADH-Deficient Humans and Mice. Ann Clin Transl Neurol. 2025 Nov;12(11):2193-2205. doi: 10.1002/acn3.70148. Epub 2025 Jul 31.
- Derived from this study: PubMed 38658850Tokatly Latzer I, Roullet JB, Afshar-Saber W, Lee HHC, Bertoldi M, McGinty GE, DiBacco ML, Arning E, Tsuboyama M, Rotenberg A, Opladen T, Jeltsch K, Garcia-Cazorla A, Julia-Palacios N, Gibson KM, Sahin M, Pearl PL. Clinical and molecular outcomes from the 5-Year natural history study of SSADH Deficiency, a model metabolic neurodevelopmental disorder. J Neurodev Disord. 2024 Apr 24;16(1):21. doi: 10.1186/s11689-024-09538-9.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Phillip L Pearl, MD study chair
Boston Children's Hospital/Harvard Medical School
K. Michael Gibson, PhD study chair
Washington State University
4 sites in 4 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Succinic Semialdehyde Dehydrogenase Deficiency, run by Boston Children's Hospital at 4 sites in 4 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 13 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in United States, Germany, Spain, United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Melissa L DiBacco, MD (617-919-4617, melissa.dibacco@childrens.harvard.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Clinical Severity Score (time frame: 5 Years). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03758521, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Jan 2026.