A New Challenge For Vanderbilt Doctors: Diagnose The Most Elusive Genetic Diseases

Dec 18, 2015

Some people have genetic diseases so rare or unusual that doctors can't even diagnose them.

This means, a patient comes in with problems — sometimes several serious, seemingly unrelated problems — and no one can figure out what gene is causing it. It can be frustrating, if not downright scary, for someone whose health is at stake.

But a new network of doctors around the country, overseen by the National Institutes of Health, has made it their task to help these patients, in an attempt to either name their rare genetic disorders or discover completely new ones.

'They Didn't Find Anything This Time'

On a sunny fall afternoon, 14-year-old Maggie Hall is helping feed the family's pet pigs and billy goats on a farm in Cookeville.

“The pig with the pink feet is Bentley," she explains. "The one that is solid black, the big one, is Mr. Wiggles.”

Really, though, her dad Mike is doing most of the work. “The kids swear up and down they'll take care of them and feed them everyday, and that lasts for two or three days, maybe.”

“I feed the cat!” says Maggie, indignantly.

Maggie is, in many ways, a standard teenager. She likes bickering with her dad and baking Christmas cookies with her mom. But one evening, about five years ago, when Maggie was 8, her parents noticed some changes that didn’t seem normal.

“We were just throwing the ball back and forth, and I noticed Maggie was having a lot of difficulty catching it," Mike says. "A little bit later that night, we were playing a game of Monopoly, and she couldn’t find her game piece on the board.”

It turned out, Maggie was starting to go blind.

Her parents took her to a local doctor, who didn't understand what was happening. Then they took her to doctors at Vanderbilt, Emory and Mayo Clinic. She was given test after test, but the doctors could not figure it out — except that it was probably genetic.

About a year-and-a-half ago, the disease got worse, this time with Maggie's muscles. At one point, she could barely do physical activity, Mike says. "We went on a trip out of town and had to bring her back in a wheelchair."

Doctors kept ruling out diseases. Their guesses were getting more alarming, like multiple sclerosis and muscular dystrophy.

"We’d almost [be] afraid of a diagnosis," Mike says. "We're so afraid of bad news that it was almost like, 'OK, they didn’t find anything this time? Good.' "

Unnamed And Undiscovered

Maggie Hall and patients like her have already gone through a "diagnostic odyssey," says John Newman, one of the lead doctors at the network's site at Vanderbilt University Medical Center.

"They go from doctor to doctor and medical center to medical center, and sometimes the very best medical centers," he says. "If it’s a disease that no one has written about or knows, they get a different opinion at each place."

Vanderbilt, in Nashville, is one of six new sites in the $120 million program called the Undiagnosed Diseases Network. Over the next four years, doctors at teaching hospitals around the country — in Boston, Los Angeles, Stanford, Houston, Nashville and Durham, N.C. — will collaborate with the NIH to see hundreds of patients, share data and swap testing methods.

Dr. John Phillips, one of the lead doctors at Vanderbilt's undiagnosed diseases clinical site, opens a container filled with frozen DNA samples. Vanderbilt is a repository for DNA samples across the new NIH network.
Credit Emily Siner / WPLN

The process starts with something that seems mundane: paperwork. Patients send in inches, or even sometimes feet high, of medical records, like x-rays and biopsies.

"Sometimes just by putting together all of the medical records from a patient from all of the different places that they have been seen, and really digging through all of the details, you can find information that might be able to help lead to a diagnosis," says Anastasia Wise, a national coordinator of the network.

Patients also get an intensive one-week evaluation, where they're seen by different specialists who can discuss what they're finding.

19,000 Genes Left

Then comes the more experimental stuff, including detailed genome and exome sequencing that most doctors don't have access to. If a genetic anomaly is found, another lab can model it on real living things — specifically, zebra fish and fruit flies — to see if it causes the same symptoms. (Yes, zebra fish may help diagnose some patients.)

“It’s really taking cutting-edge research techniques and applying them to these patients, [who] have typically received all of the standard clinical testing that’s available by the time they come to the undiagnosed diseases network,” Wise says.

Still, success is far from guaranteed. The NIH started working on undiagnosed diseases back in 2008, before it expanded into this new multi-hospital network. In its first two years, it saw 160 patients. About a quarter were diagnosed, and it only found two completely new genetic diseases. The rest were just very rare.

But John Phillips, another lead doctor at Vanderbilt's new clinical site, says he expects to find more, now that doctors and labs across the country can collaborate.

"We have perhaps 23,000 genes or so, but we only now know diseases that go with 4,000 of them," he says. "So logic would say there are 19,000 genes that could cause a disease but no one has ever proven it.”

And often, he says, that can lead to finding treatment for the disease or ways to manage the symptoms.

One of the first patients accepted to the Undiagnosed Diseases Network site at Vanderbilt? Maggie Hall. Her dad, Mike, says they're cautiously optimistic.

“We’ve gotten to the point now where we say, 'Eh, they’re probably not going to find anything,' " he says. 

Maggie has been doing better recently. She can walk well again, and she's gaining back some muscle weight. Her parents are hoping for some new information that will help Maggie manage her disease and stave off relapses in the future.

They care less about what it's called. Her health, Mike says, is more important than a name.

"She might just have Maggie Hall syndrome," he says.