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NIH UNI Study: Urea Cycle Disorders, Nutrition and Immunity

Frequently Asked Questions about the UNI Study

What is this study about?

The main goal of our study is to learn about the dietary complications in patients with UCD and understand the effect(s) that those complications may have on the function of the immune system. We will perform a detailed nutritional and immunologic assessment for all study participants and will then offer the combined seasonal influenza/H1N1 vaccine as well as the Hepatitis A vaccine. Both of these vaccinations are recommended for all UCD patients. After a few months we will measure whether or not the study participant's immune system was able to respond appropriately to that vaccine.

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What are we NOT trying to do with this study?

We are NOT testing any new medicine or procedure to treat or cure UCD. At the National Institutes of Health (NIH), we are interested in research. Although we are happy to provide advice for people enrolled in our study, we are not able to take over the long-term care of a person with UCD. To enroll in our study, you (your child) must have a confirmed diagnosis of UCD. We are not able to provide a "first time" diagnosis or regular metabolic care.

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Who can participate in this study?

To be in our study a person must:

  1. Be at least 2 years of age
  2. Have a biochemically confirmed diagnosis of UCD or a related disorder
  3. Be able to travel to and be admitted to the NIH Clinical Center in Bethesda, Maryland for 2 separate visits about 2-3 months apart. The first visit will typically be 2-3 days long and the second visit will typically last for 2 days.

There are some reasons why someone may not be able to join the study. We can not enroll anyone who:

  1. Is under 2 years of age
  2. Is being treated for an intercurrent infection with antibiotics, has evidence of an acute infection, or has hyperammonemia (a high level of ammonia)
  3. Has received another vaccine or immune modulating drug within the past 6 months
  4. Is currently living in a hospital
  5. Does not have a local/regular physician who manages their UCD

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What is involved in the study?

One of our team members will first need to talk with you on the phone to see if you are (your child is) eligible to join the study. Joining the UCD study will involve at least two visits to the National Institutes of Health in Bethesda, Maryland. The first visit will typically last 2-3 days and the second visit will occur 2-3 months later and will typically last for 2 days. Most study participants will be admitted as inpatients. Some participants may also need to return to the NIH for an intermediate visit 1 month after their initial visit. This will depend on age and vaccination history.

When you (your child) first arrive at the NIH we will have an informed consent discussion to review the risks and benefits of the study and confirm that you are (your child is) willing to join the study. You (your child) will meet with a geneticist who will ask about medical and family history and do a physical exam like in any doctor's office. We will ask all study participants to allow us to collect urine, draw blood, and perform a detailed nutritional and immunologic assessment. We will suggest an additional set of evaluations for some participants that we feel is appropriate based on age and level of independence. We will explain the need for those studies to you (your child). They may include imaging studies such as a DEXA scan and a CT scan, body composition testing, energy expenditure testing, and a skin biopsy (if one has not been done). We will offer the seasonal/H1N1 influenza vaccine as well as the Hepatitis A vaccine, both recommended for all UCD patients. At the 2 to 3 month follow-up visit we will again collect urine and draw blood and will determine whether or not your (your child's) immune system was able to respond to the vaccine. You will receive the results of your (your child's) clinical testing.

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What are the benefits of participating in the study?

Possible direct benefits include:
  • Immunization for seasonal influenza/H1N1, which is standard of care for patients with UCD
  • A comprehensive nutritional and immunologic evaluation
  • Results of other clinical testing

Further, we hope the results from the study will eventually benefit other patients and families with UCD.

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What are the risks of participating in the study?

Possible risks include:
  • Pain or bruising as a result of the blood draw
  • Soreness, redness or swelling at the site of the vaccination; Hoarseness, sore or red eyes, cough, itchiness, fever, aches as a result of the vaccination.
  • Radiation exposure during the DEXA scan or CT scans.

The above risks tend to be very rare or minor. Life-threatening allergic reactions from vaccines are very rare.

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How will information about participants be kept private?

We take privacy and confidentiality very seriously. Your (your child's) medical information will be stored in a password-protected database and in a locked filing cabinet. Although we may share medical information with our colleagues, your (your child's) name will not be used. Instead a code will be used that is unrelated to your (your child's) name. The "key" to the code will be stored in a locked drawer in the office of the principal investigator or in a secure password-protected database.

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Is there any cost involved in participation?

The visit and all testing are free and there is no cost to you, your family, or your insurance company for this study. If you live locally (near the NIH) we will give you some money for meals and provide lodging if necessary. If you live further away, we will pay for your transportation to NIH (plane, car mileage, train, etc), lodging, and give you some money for meals. The NIH must arrange all travel.

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Is there any payment provided for participation?

No, you (your child) will not receive any compensation other than some food, travel and lodging expenses.

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How does someone enroll in this study?

The first step is to determine if you are (your child is) eligible to participate. Please see the frequently asked question "Who can participate in this study" above for details. If you have questions about whether you are (your child is) eligible, or if you would like to enroll, please contact us. Contact

Where else can I find information about this study on the Web?

These Web pages provide the most information about this specific study that is available on the Web. This study is also listed on along with all other NIH studies and many non-NIH studies. To find this study on, type our unique study identifier in the search box: NCT01421888. To find all studies related to urea cycle disorders, type "urea cycle disorders" in the search box.

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Last Updated: August 7, 2014