Vanderbilt Doctors Make Progress On Diagnosing Rare Mystery Diseases

Over the past year and a half, doctors and researchers in Nashville have diagnosed eight of the rarest genetic diseases. One doctor on the team at Vanderbilt University Medical Center says its progress is now speeding up.

When Maggie Hall got accepted into the Undiagnosed Diseases Network in 2015, her father Mike and mother Susan had learned not to get their hopes up. Maggie had started losing her vision when she was 8, with no apparent cause. She also had recurring bouts of muscle weakness. 

“She’s been poked and prodded and tested for five years now, and they’ve all come back negative,” he told WPLN.

But Vanderbilt had access to tests that no one else they’d been to did. Like a highly detailed exome sequencing — “like a spell check on a computer” for her genes, says Dr. John Phillips, the Vanderbilt doctor working with Maggie. What came back from the lab was a pretty straightforward answer.

“In this case, the spell check said that this gene was misspelled.”

It’s the gene NADK2, and only three other cases of this mutation have ever been documented.

Vanderbilt is one of seven medical centers in an NIH-funded network working to solve mystery diseases. So far, Vanderbilt has seen 21 patients and diagnosed eight. Phillips says more diagnoses are coming through quickly. 

But this part of the process is just the first step. “The real excitement is when the diagnosis not only explains things but [shows] that you can do something different,” he says.

In Maggie Hall’s case, Phillips is giving her a supplement — something over-the-counter — that might help her produce more of an enzyme that her body is lacking because of the gene mutation.

And for all of the waiting she’s already gone through, he says they’ll know if this treatment works in a matter of weeks.

“We realize that treatments don’t always work, but to be able to say to Maggie and her family, ‘This is a very logical thing for us to try,’ that’s very different from, ‘Your daughter has a serious problem and we don’t understand what it is,’ ” Phillips says.