About the Undiagnosed Diseases Network

What is the Undiagnosed Diseases Network (UDN)?

The UDN is a research study funded by the National Institutes of Health Common Fund. The UDN is made up of clinical and research centers across the United States working to improve diagnosis and care of patients with undiagnosed diseases.

What is the purpose of the UDN?

The UDN has two main goals:

  1. To provide answers for patients and families affected by mysterious conditions, and
  2. To learn more about rare and common diseases.

What are the UDN clinical sites?

What is unique about the UDN?

The UDN is trying to solve the most challenging medical mysteries by:

  • Bridging the gap between clinical care and research.
  • Using genetic data to try to find diagnoses.
  • Working with researchers to figure out how diseases affect the body, which may lead to treatments.
  • Training other doctors, nurses, genetic counselors, and scientists to use this new approach.

What is an undiagnosed disease?

An undiagnosed disease is a medical condition without a known cause despite a lot of evaluation.

What is a rare disease?

A rare disease is a disease that affects fewer than 200,000 people in the United States. There are so many separate rare diseases that, overall, 1 in 10 people have a rare disease.

Who is eligible for the UDN?

Eligible patients:

  • Are at least one month old.
  • Have a disease or condition that remains undiagnosed despite thorough evaluation, ongoing care and follow up by a healthcare provider.
  • Are able to travel.

Applying to the UDN

How do I apply to the UDN?

  1. Before applying to the UDN, it is important to discuss it with a healthcare provider.
  1. Then, you need a working email address and access to a computer and the Internet.
  1. Ask your healthcare provider to write a referral letter. The letter should include:
  • A summary of medical problems
  • Date when symptoms were first noticed
  • Previous diagnoses
  • History of evaluations and tests
  • History of treatments and medications
  • Current medications
  • Family history
  • Healthcare provider’s diagnostic thoughts
  • For pediatric patients, prenatal and birth history should also be provided.

Click here to see a set of sample referral letters .

  1. Fill out the application through our online system, which we call the UDN Gateway. You will also need to submit the referral letter directly to the Gateway. It should take less than 20 minutes to complete this whole process. DO NOT email the application or referral letter to the UDN.
  2. When the UDN has received your application, you will receive a confirmation email. The UDN will also let you know if more information and/or medical records are needed before your application can be reviewed.

Why is a healthcare provider’s referral required?

The UDN evaluation is only one part of your medical care. Your healthcare provider has been with you before the UDN evaluation and will likely continue to provide your medical care after the UDN evaluation. If you are accepted into the UDN study, the UDN will provide information from the evaluation to you and to your healthcare provider. Your healthcare provider will be responsible for your follow-up medical care.

I don’t have a primary healthcare provider and I don’t have health insurance. Can I still apply?

Yes, but you will need to get a referral letter from a healthcare provider. If you receive care in a clinic or other healthcare setting, you can discuss your application with a member of the medical team.

Having insurance is not a requirement to participate in this study. We aim to minimize your out of pocket costs as much as possible. If you are accepted into the UDN, talk with your clinical site representative about any possible charges you may incur.

What happens with my application?

  1. Most likely, your application will be assigned to the UDN clinical site that is closest to where you live. Sometimes it will be assigned to a clinical site based on other factors.
  2. The assigned UDN clinical site will then contact you, typically within one month of application submission, to request additional information, such as:
  • Medical records
  • Laboratory studies
  • MRI, X-ray, or CT images (can be sent on CD)
  • Photographs or videos
  • Pathology slides and reports
  • For pediatric patients: growth curves and newborn records

In order to help with the application review process, you can begin to collect these records now. However,please do not send this information until you receive specific instructions to do so from a UDN clinical site.

Please use only the specific contact information that you receive from the clinical site for UDN-related emails or to submit medical records. Please do not send these materials to the UDN Coordinating Center.

  1. The UDN team will review your application and make a decision about acceptance into the study.

If I apply, does that automatically mean that my application will be reviewed?

Yes. Once all materials have been received, UDN review is expected to take about 6-8 weeks.

If I apply, does that automatically mean I can go to a UDN clinical site?

No. The UDN can only accept a small number of participants. The UDN team reviews each application very carefully to decide who can be accepted into the study. Even if you are not accepted, you might receive some useful feedback about your medical condition.

How will I find out the UDN’s decision?

We will contact you and your referring provider.

Can I choose which UDN clinical site I’m assigned to?

You may ask to be assigned to a specific UDN clinical site on your application if you want to. However, there is no guarantee that you will be assigned to that site.


UDN Evaluation Process

If I am accepted into the UDN study, what happens next?

You will work with a UDN clinical site to determine the dates for a 2-5 day visit to the clinical site. You will travel to your assigned UDN clinical site for a medical and research evaluation. You may also be asked to provide copies of additional medical records.

What will happen at the clinical site?

You will be asked to enroll in the study and sign a consent form. You will also be asked to provide information about the health of your family members and to give permission for photographs, blood samples, and other samples (such as skin) to be taken.

You may be asked to send a blood sample for genetic testing to the clinical site several weeks before your clinical evaluation. Based on the types of symptoms you have, various medical specialists will evaluate you during your clinical site visit. You will also be asked to fill out some forms and surveys regarding your health and your experience with the UDN before, during, and after the clinical site visit.

The UDN works to provide a similar participant experience, however, practices may vary by clinical site.

Will participants also have DNA tested as part of this study?

Most, but not all of the time, blood will be taken for DNA testing. The hope is that DNA testing will help the UDN team diagnose conditions. You will be informed about how your DNA will be used. If available and willing to participate, your biological family members may also provide DNA samples for testing. Your UDN clinical site will determine which family members should be asked to participate. More information about genetic testing through the UDN is available in the Genetic Testing Handout .

There may be people who have a history that suggests that the undiagnosed disease is not genetic. If you suspect an environmental cause of your condition, be sure to say so on the application.

Why might my family members need to be tested?

If your DNA is being analyzed, it is helpful to also get blood from your family members to compare their genetic results with your genetic results. This helps the UDN team to assess the meaning of your results.

What if my family members are unable or unwilling to participate?

You may still qualify to participate. However, this situation may make it harder for the UDN team to find a diagnosis.

What laboratories will do the genetic testing?

Will the UDN evaluations give me a diagnosis?

The goal is to give you a diagnosis, but this may not happen.

Will I receive treatment through the UDN?

No, treatment will usually not be provided as part of the UDN. Treatment will remain your and your referring healthcare provider’s responsibility. But you and your provider may receive treatment recommendations from the UDN.

What is the cost for participating if accepted?

We aim to minimize your out of pocket costs as much as possible. If you are accepted into the UDN, talk with your clinical site representative about any possible charges you may incur.

What happens after the UDN evaluation?

After the UDN evaluation, you and your referring provider will receive the information from the evaluation. Long term care will not be provided by the UDN. Some UDN participants may be eligible for other research studies at the UDN site or other academic centers.


Contact Information

Who can I reach if I still have more questions?

You can call or email the Gateway Helpdesk at the UDN Coordinating Center to find out more about:

  • Participating in the UDN research project
  • Eligibility
  • What to include in the referral letter
  • Status of your application

Hours: Monday–Friday, 9am – 5pm ET
Email: UDN@hms.harvard.edu
Phone: 1-844-746-4836 (1 844 Ring UDN)

Note: please do not contact the main hospital of the UDN clinical sites.