Applications Received


Applications Under Review


Participants Accepted


Participants Evaluated


Participants Diagnosed

Our Current Research

Model Organisms

The Model Organisms Screening Center (MOSC) for the UDN is a collaborative center with investigators from Baylor College of Medicine and University of Oregon. The MOSC allows for world-renowned experts in Drosophila (fruit fly) and Zebrafish genetics and biology to tackle undiagnosed diseases.


Genes of interest


Meet Our Participants

During the first few years of her life, the participant was developing as expected. She learned to walk at 11 months and talk at 12 months, and was described as a sweet, mature, well-behaved child who could sing entire songs and write complete sentences. Upon entering kindergarten, she succeeded academically, … read more

tall stature, occipital protuberance, atrial fibrillation

Starting in early childhood, the participant experienced chronic diarrhea with excess fat in his stool (steatorrhea), fragile and sagging skin (cutis laxa), and poor wound healing. At 11 years old, a heart murmur was detected. Later in life, the participant was diagnosed with atrial fibrillation and heart muscle disease (cardiomyopathy). … read more

Shortly after birth, the patient was noticed to have decreased tone and difficulty breathing. She struggled to drink from a bottle and would breathe liquids into her airway (aspirate). At 6 months, a G tube was placed. Currently she struggles with chewing and swallowing and is unable to drink out … read more

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New UDN participant page (058) describes a 2 year old girl with an autoimmune condition. Despite a very thorough workup, the cause of her symptoms has not been found. Please review her page and reach out using the "Contact Us" form if you know someone with similar symptoms.

"A few years ago, the U.S. National Institutes of Health expanded an existing program called the Undiagnosed Disease Network (UDN) to include a group dedicated to using fruit flies (as well as fish) to figure out which of several genes identified using a genomic medicine approach is the cause of a given rare or new disease. The group, led by Hugo Bellen, a fruit fly biologist at Baylor College of Medicine, introduces changes into the fly genome that mimic changes found in genes from human patients. Sometimes they even insert a human gene into a fly. Then they watch the flies to see if they get symptoms that resemble the symptoms of the human disease."

The UDN recently participated in Mediaplanet's Rare Diseases campaign, which was distributed through USA TODAY on March 15th, 2018 and is published online. For the full campaign, visit

UDN Participant 057's early development was typical and he began walking at 15 months. However, his parents noticed early on that he was not using his left arm and that it seemed to cause him pain. He experienced episodes of arm paralysis and leg weakness that would last for several days. He was found to have decreased muscle tone and weakness in his left arm. The participant also had trouble feeding and swallowing, which required a G-tube. He also has mast cell accumulation in his skin that causes severe itching. He has had two seizures. Despite extensive evaluation by the UDN, he remains undiagnosed at this time. We are looking for similar patients that could help us better understand his condition. Please take a moment to review his page and contact us through our website if you know someone with similar symptoms.

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