Many mysterious disorders involve the brain and nervous system

Since opening a new research branch, federal researchers have been deluged with medical mysteries. 

Since opening its doors two years ago, the National Institutes of Health's Undiagnosed Diseases Program has been deluged with requests for medical sleuthing assistance, especially among people with neurological symptoms.

In a summary of the agency's work thus far, published Thursday, leaders of the Bethesda, Md.,-based program said more than half of the cases they have accepted involve undiagnosed symptoms of the brain and central nervous system. Undiagnosed disorders involving pain, psychiatric symptoms and the gastrointestinal and immune systems also cropped up more frequently. Another common category of mystery cases ended up being diagnosed as fibromyalgia or chronic fatigue syndrome.

The overwhelming response to the opening of the program apparently stunned researchers and points to the need for more places where patients with long-standing undiagnosed health problems can see a team of specialists. At the NIH clinic, patients typically meet with a variety of specialists from the 27 branch institutes and centers over a one-week visit. Biological and genetic tests are conducted, including gene testing of family members.

"[T]he NIH was often the first opportunity for many patients to access a coordinated multidisciplinary evaluation," the authors of the paper said. The review appears in the journal Genetics in Medicine.

The program opened for applications in May, 2008, and received 1,191 cases for review. "The applications may represent years of evaluation by multiple doctors at more than one medical facility--but with no conclusive diagnoses," Dr. William Gahl, UDP director, said in a news release.

So many requests were received that the program temporarily stopped accepting new applications. The process will resume in November.

More than 300 cases have been accepted into the program and 39 have been solved. Most of those cases involved diseases that have been previously identified. Doctors are trained in diagnosing about 500 disorders, but about 6,500 very rare disorders are known to exist beyond the common ones. The NIH program has already identified a new disorder called arterial calcification due to deficiency of CD73. CD73 is a protein that protects arteries from calcifying. The institute is also set to report on a second new disorder later this year.