Glycogen Storage Disease Type IGSD-DIETNCT06852612
Dietary Treatment Strategies and Metabolic Control in Glycogen Storage Disease Type I
A study testing Fructose and Fructose and galactose in people with Glycogen Storage Disease Type I, run by Insel Gruppe AG, University Hospital Bern at 2 sites in Switzerland.
Trial summary
The present project will specifically assess metabolic effects of dietary interventions with controlled intake of fructose and fructose/galactose in GSDI, with the aim to provide evidence whether relaxed dietary restrictions of fructose and galactose may be justified in treatment recommendations at least for adults… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Glycogen Storage Disease Type I
- What is being tested?
- Fructose and Fructose and galactose
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 2 sitesSwitzerland
- Study dates
- 24 Apr 2025to Mar 2027
- Phase
- Interventional
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Genetically and/or enzymatically confirmed diagnosis of GSDI (GSDIa or GSDIb)
- Male or female ≥ 18y
- Restriction of fructose intake in usual dietary treatment
- Written informed consent
Who cannot join
- Non-compliance with routine dietary treatment
- Pregnancy or lactation
- Liver transplant
- Recurrent hospitalisations due to metabolic decompensation within the last 12 months
- Severe chronic kidney disease with glomerular filtration rate (GFR) < 30 ml/min
- For GSDIb: Severe, uncontrolled symptomatic inflammatory bowel disease
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland2 sites, 2 recruiting
- Recruiting
Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital
Bern, 3010
Michel Hochuli, MD, PhD
- Not yet recruiting
Department of Endocrinology, Diabetology and Clinical Nutrition, University Hospital Zurich
Zurich, 8091
Laura Horka, MD, +41 44 255 36 20, laura.horka@usz.ch
About this study
Official title: Dietary Treatment Strategies and Metabolic Control in Glycogen Storage Disease Type I (GSD-DIET)
The present project will specifically assess metabolic effects of dietary interventions with controlled intake of fructose and fructose/galactose in GSDI, with the aim to provide evidence whether relaxed dietary restrictions of fructose and galactose may be justified in treatment recommendations at least for adults, which would considerably enlarge food choice in everyday life of the patients with an expected positive impact on the quality of life of patients with this rare disorder.
Read the detailed description
To assess relaxed restriction of fructose and fructose/galactose intake on secondary metabolic alterations in GSDI, (i) by looking at the traditional parameters for assessing metabolic control in clinical chemistry (lactate, triglycerides, uric acid), and (ii) by using a broad analytical approach relying on targeted metabolomics/lipidomics.
It is hypothesized that relaxed restrictions on the intake of fructose and/or galactose as part of the diet in everyday life may lead to an increase in blood lactate levels (=primary outcome), triglycerides, and uric acid to a certain degree compared to baseline. However, this increase is expected to remain within a range that is not clinically relevant for adult patients, especially when fructose/galactose intake is not excessive and stays within the usual daily allowances for healthy individuals, as planned in this study.
- Conditions
- Glycogen Storage Disease Type I
- Being tested
- Fructose, Fructose and galactose
- Keywords
- Gsd1, Metabolism, Fructose, Galactose
- Medical subject headings
- Glycogen Storage Disease Type I
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FructoseDietary supplement
40g fructose (free and bound, max amount of fructose from added free sugar/saccharose 25g)
Fructose and galactoseDietary supplement
10g galactose (mostly from lactose) plus 40g of fructose (free and bound, max amount of fructose from added free sugar/saccharose 25g)
| Study group | Role | What they receive |
|---|---|---|
| Diet with additional fructose intake | Experimental | Not described Receives: Dietary Supplement: Fructose |
| Diet with additional fructose and galactose intake | Experimental | Not described Receives: Dietary Supplement: Fructose and galactose |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in lactate during the dietary intervention compared to baseline under the usual diet
Lactate belongs to the parameters of secondary metabolic disturbance traditionally used to estimate metabolic control in GSDI in routine clinical practice (lactate, triglycerides, uric acid). Redundant measurements of lactate are performed in blood as well as in collected urine.
Measured: 4 Weeks
Secondary outcomes (4)
Change in plasma triglycerides during the dietary intervention compared to baseline (as parameters traditionally measured together with lactate to estimate overall metabolic control)
Measured: 4 Weeks
Change in plasma uric acid during the dietary intervention compared to baseline (as parameters traditionally measured together with lactate to estimate overall metabolic control)
Measured: 4 Weeks
Plasma metabolite changes in targeted metabolomics during the dietary intervention compared to baseline measurements.
Measured: 4 Weeks
Plasma metabolite changes in targeted lipidomics during the dietary intervention compared to baseline measurements.
Measured: 4 Weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Feb 2025
- Study start24 Apr 2025
- Primary completionMar 2027 (estimated)
- Study completionMar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Glycogen Storage Disease Type IStudies of the same condition, open and under way.
- More trials run by Insel Gruppe AG, University Hospital BernThe 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Insel Gruppe AG, University Hospital Bern
- Sponsor type
- University, hospital or other
- Collaborators
- University of Zurich, University Hospital Freiburg, University Hospital Heidelberg, Medical University Innsbruck
- Responsible party
- Sponsor
- Investigators
- Michel Hochuli, MD, PhD, Principal investigator, Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06852612
- Sponsor's protocol ID
- 2024-02154
- Acronym
- GSD-DIET
- Status last verified
- May 2026
- First submitted
- 24 Feb 2025
- Last updated
- 12 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data (IPD) will be made available upon reasonable request to the principal investigator.
Study at a glance
From the registry record, last updated by the sponsor on 12 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dietary Treatment Strategies and Metabolic Control in Glycogen Storage Disease Type I (GSD-DIET)
- ClinicalTrials.gov ID
- NCT06852612
- Acronym / sponsor ID
- GSD-DIET / 2024-02154
- Conditions
- Glycogen Storage Disease Type I
- Keywords
- Gsd1, Metabolism, Fructose, Galactose
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- Insel Gruppe AG, University Hospital BernUniversity, hospital or other
- Collaborators
- University of Zurich, University Hospital Freiburg, University Hospital Heidelberg, Medical University Innsbruck
- Study start
- 24 Apr 2025 (actual)
- Primary completion
- Mar 2027 (estimated)
- Study completion
- Mar 2027 (estimated)
- First posted
- 28 Feb 2025 (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.
The present project will specifically assess metabolic effects of dietary interventions with controlled intake of fructose and fructose/galactose in GSDI, with the aim to provide evidence whether relaxed dietary restrictions of fructose and galactose may be justified in treatment recommendations at least for adults, which would considerably enlarge food choice in everyday life of the patients with an expected positive impact on the quality of life of patients with this rare disorder.
Detailed description
To assess relaxed restriction of fructose and fructose/galactose intake on secondary metabolic alterations in GSDI, (i) by looking at the traditional parameters for assessing metabolic control in clinical chemistry (lactate, triglycerides, uric acid), and (ii) by using a broad analytical approach relying on targeted metabolomics/lipidomics.
It is hypothesized that relaxed restrictions on the intake of fructose and/or galactose as part of the diet in everyday life may lead to an increase in blood lactate levels (=primary outcome), triglycerides, and uric acid to a certain degree compared to baseline. However, this increase is expected to remain within a range that is not clinically relevant for adult patients, especially when fructose/galactose intake is not excessive and stays within the usual daily allowances for healthy individuals, as planned in this study.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Diet with additional fructose intake | Experimental | Dietary Supplement: Fructose |
| Diet with additional fructose and galactose intake | Experimental | Dietary Supplement: Fructose and galactose |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Genetically and/or enzymatically confirmed diagnosis of GSDI (GSDIa or GSDIb)
- Male or female ≥ 18y
- Restriction of fructose intake in usual dietary treatment
- Written informed consent
Key exclusion criteria (6 listed)
- Non-compliance with routine dietary treatment
- Pregnancy or lactation
- Liver transplant
- Recurrent hospitalisations due to metabolic decompensation within the last 12 months
- Severe chronic kidney disease with glomerular filtration rate (GFR) < 30 ml/min
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 |
|---|---|---|
| Fructose40g fructose (free and bound, max amount of fructose from added free sugar/saccharose 25g) | Dietary supplement | Diet with additional fructose intake |
| Fructose and galactose10g galactose (mostly from lactose) plus 40g of fructose (free and bound, max amount of fructose from added free sugar/saccharose 25g) | Dietary supplement | Diet with additional fructose and galactose intake |
Primary outcome
Change in lactate during the dietary intervention compared to baseline under the usual diet
Time frame: 4 Weeks
Lactate belongs to the parameters of secondary metabolic disturbance traditionally used to estimate metabolic control in GSDI in routine clinical practice (lactate, triglycerides, uric acid). Redundant measurements of lactate are performed in blood as well as in collected urine.
4 secondary outcomes
Change in plasma triglycerides during the dietary intervention compared to baseline (as parameters traditionally measured together with lactate to estimate overall metabolic control)
Time frame: 4 Weeks
Change in plasma uric acid during the dietary intervention compared to baseline (as parameters traditionally measured together with lactate to estimate overall metabolic control)
Time frame: 4 Weeks
Plasma metabolite changes in targeted metabolomics during the dietary intervention compared to baseline measurements.
Time frame: 4 Weeks
Plasma metabolite changes in targeted lipidomics during the dietary intervention compared to baseline measurements.
Time frame: 4 Weeks
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 12 May 2026.
- Individual participant dataSharing planned: Yes. Individual participant data (IPD) will be made available upon reasonable request to the principal investigator.
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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.
Michel Hochuli, MD, PhD principal investigator
Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fructose and Fructose and galactose in people with Glycogen Storage Disease Type I, run by Insel Gruppe AG, University Hospital Bern at 2 sites in Switzerland.
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 4 inclusion and 6 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 12 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Switzerland. 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 Michel Hochuli, MD, PhD (+41 31 664 03 18, michel.hochuli@insel.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in lactate during the dietary intervention compared to baseline under the usual diet (time frame: 4 Weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 12 May 2026.