Interested in participating? Learn about which studies might be right for you.

Rare disease patient group icon
STUDY 1 | Clinical Interventional

GlucoGene™ Gene Therapy Phase 3 Study


GSDIa gene therapy icon

Have been diagnosed with GSDIa

Ages 8+ icon

Are 8 years of age or older

Dinner plate and cutlery icon

Are currently receiving cornstarch regularly as part of your dietary regimen

Why are we doing this study?

Ultragenyx is sponsoring this study to find out if DTX401 is a safe and effective treatment for adults and children with GSDIa. The goal of this study is to evaluate if DTX401 can help people with GSDIa maintain or improve blood sugar levels with less or no cornstarch and reduce the risk of hypoglycemia.

GlucoGene™ Gene Therapy for the Treatment of GSDIa
Compass icon

Additional travel support may be available

Ultragenyx recognizes that your participation in clinical research has an impact on your (and your loved ones’) time. We may provide compensation and travel support for participation in our clinical trials—the details may vary program to program. You will learn more during the consent process.

What is involved?

All participants will receive DTX401, either initially or after ~1 year (if still eligible).

All patients who receive DTX401 will be offered enrollment in an optional long-term follow-up study.

clock icon


Approximately 2 years

Gene therapy strand icon


An investigational gene therapy called DTX401 is being tested for possible use in the treatment of glycogen storage disease type Ia (GSDIa).

Clinic icon

Study visits

  • 9 clinic visits that require a 1-2-night stay
  • 4 outpatient visits
  • 16 outpatient/home-health visits

What you can expect

IV bag icon

Infusion of study and/or placebo medicine into your arm

Medical questionnaire clipboard icon

Medical questionnaires

Glucose monitoring* medical record icon

Continuous glucose monitoring*

Apple icon

Diet and cornstarch assessment

Plate with fork and spoon icon**

Controlled fasting challenge**

Note taking diet diary icon

Diet diary

Lab test tubes icon

Lab tests

*Study participants will not see these results

**At the hospital

Interested in participating or have questions? Get started

Understanding Gene Therapy

Gene therapy is the introduction, removal, or change of genetic material in the cells of a person. For certain rare genetic diseases, gene therapy offers the potential for treatment that could have a significant impact on the lives of patients. Find out more details, including how gene therapies are designed to work.

Dig Into the Science

Global icon
STUDY 2| Nonclinical Online Observational

GSDIa Odyssey Study


GSDIa icon

Have been diagnosed (or are the caregiver for someone) with GSDIa

United States map icon

Live in the United States and have received medical care in the US in the past 7 years


Did you know you and your child’s unique medical history can have a positive impact on the future care for the GSDIa community? Anonymized, real-world data from patient medical records can be used to help advance GSDIa understanding and potentially improve the quality of care.

Sign up online. It only takes a few minutes.

For more information, see the PicnicHealth study website or connect with a Patient Enrollment Liaison (PEL) team member.

GSD Odyssey Study logo
House icon

No TREATMENT or visits

This study allows participants to get their medical records collected, encrypted, and digitized for free—and they’re yours to keep, use, and share as you wish.

Participate in nonclinical research from your home, and help make a difference in GSDIa care.

What you need to do

Online signup icon

Step 1

Sign up: Create a free PicnicHealth account (learn about PicnicHealth below), and sign the consent forms (it only takes a few minutes). Provide the names of your doctors, and we’ll take it from there.

Medical Health Records icon

Step 2

Wait for your records: Your medical records are collected and digitized into your own PicnicHealth Timeline.

What you can expect

Digital medical record icon
Access and share your digitized medical records
Email icon
Receive information on new research opportunities
Gift card representation
$25 gift card (once eligibility is confirmed)
GSDIa research icon
Contribute to GSDIa research
Research collection data icon


GSDIa research is hard to conduct. By collecting and analyzing anonymized patient data, researchers may gain a greater understanding of GSDIa, with the potential to advance future care for patients.

Interested in participating or have questions? Get started


Ultragenyx Pharmaceutical is working in partnership with PicnicHealth, a company that collects, digitizes, and encrypts medical records. If you sign up to participate in this study, you’re agreeing to share your anonymized medical records with researchers and organizations working with PicnicHealth on the study.

Researchers only receive records stripped of any information that could be used to identify you personally. Outside of that, no one outside of PicnicHealth will be able to see your medical record timeline unless you choose to share them.

Interested in taking part in this study?

Get Started

To learn about current and future studies, you only need to fill out the form once.
*All fields are required.


By submitting this form, you confirm that a diagnosis of GSDIa has been made by a medical professional.

If you would like to know more about your privacy and the data you submit and data we collect while you are on this website, please see below or visit our privacy policy.

What happens after you submit your information?

Our Patient Enrollment Liaison (PEL) team will contact you by email or phone within one business day to discuss your study eligibility and answer questions.

If you choose to be contacted by email, be sure to check your spam folder for an email from [email protected], if it’s not in your regular inbox.

Email icon

Got Questions?

Email our PEL team about current and future medical research opportunities.

Glycogen Storage Disease Ia (GSDIa) patient representation Glycogen Storage Disease Ia (GSDIa) patient representation

Patient portrayal.

GSDIa is the most severe genetically inherited glycogen storage disease. It is caused by a defective gene for the enzyme glucose-6-phosphatase-α, resulting in the inability to regulate glucose. Hypoglycemia in patients with GSDIa can be life threatening, while the accumulation of glycogen in certain organs and tissues can impair their ability to function normally.

If you are thinking about joining a study, our Patient Enrollment Liaison (PEL) team is here to help. Every member of our PEL team has a robust professional background and clinical expertise and experience to help answer your questions. Your PEL team member will assist in exploring clinical and nonclinical studies and can determine if you or someone you care for may be eligible to take part. Your PEL is here to make the process as easy as possible.

To speak with a PEL about current and future medical research opportunities, please email our PEL team at [email protected].

When you voluntarily submit your personal data, Ultragenyx stores and processes this information in an electronic database consistent with our Privacy Policy. Ultragenyx will use this information to contact you to fulfill your request regarding Ultragenyx research opportunities.

Clinical and nonclinical studies provide invaluable information to treat, diagnose, or discover new breakthroughs in treating rare and ultra-rare diseases. By choosing to participate in research, you may help advance treatments, provide crucial insights, and ultimately improve the quality of life for others living with a rare or ultra-rare disease. You might also benefit from learning more about your condition, gain access to specific care, or achieve faster access to treatment. All efforts of participation, big and small, can make a difference.

Ultragenyx is leading the future of rare disease medicine. We leverage our experience, insight, and commitment to help move the rare disease community forward. Our primary goal is to provide medicines to those with limited options, and to help patients face rare disease head on with courage and confidence.

Please Enter Only US Phone Number

We will get backto shortly