They are patients with diseases that mystify doctors, people whose symptoms are dismissed as psychosomatic, who have been given misdiagnosis upon misdiagnosis.
They have confounded experts and have exhausted every hope save one. And so they wind up in the Undiagnosed Diseases Network, a federally funded project that now includes 12 clinical centers, including one at the National Institutes of Health in Bethesda, Md.
Researchers in the network pursue every possible clue — gleaned from genetics, imaging, biochemistry, clinical exams — to discover what is wrong with these patients.
In a recent study, 1,519 patients were referred to the network, but less than half were accepted for intensive evaluation at no charge. The network completed evaluations of 382 participants and found a diagnosis for 132 of them. (In the time since the study ended, the investigators have diagnosed another 128 patients.)
For some, there was good news: a treatment, often a drug that was already on the market for another condition.
Yet even patients who come away with a diagnosis but without a treatment, say the experience can be rewarding.
"Patients find it really valuable even just to give a name to the enemy," said Dr. Euan Ashley, a geneticist at Stanford University and co-director of the network.
Those who come away without a diagnosis or treatment are told that if the science improves and an answer for them emerges, the network will contact them.
"We never give up," Dr. Ashley said.