There are thousands of rare diseases that many doctors never see in a lifetime of practice. That makes diagnosis, understanding and treatment that much more complicated.
"There are 30 million people who are affected by rare diseases in the U.S. Unfortunately there are only about 200 rare diseases where is any active research ongoing," explained Dr. Kasturi Halder, who heads Notre Dame's Center for Rare and Neglected Diseases.
"For the vast majority of rare diseases, there are no cures," she adds.
Dr. Halder says centers like hers aim to become clearing houses for information, where clinical data for patients with any one of these 7,000 rare conditions can be gathered and stored.
"We really have to make information about rare diseases non rare," she said. "What's missing for these rare disease patients is data about their condition. ... If you have a few hundred cases your understanding of that disease is vastly different than if you have three."
But for that to happen, a rare condition has to be recognized, and diagnosed. Because these conditions are so rare, they're often hard for doctors to identify.
Such was the case with one Chicagoland family.
At Christmas, Patricia Millet was a happy busy grandmother. Just weeks later, she began rapidly losing her ability to walk and speak, was having horrible hallucinations and could barely feed herself.
Her children and husband were mystified, as were the emergency room doctors who saw her four times in three weeks.
"The hardest thing was there was no information. The MRI didn't show anything... They would send us home and we would hope it got better. And it would get much much worse," explained Tess Millet, recalling how frustrating it was to watch her mother deteriorate and suffer with no idea what was going on.
Finally, a neurologist made the diagnosis: Creutzfeldt Jakob Disease, a condition so rare it literally strikes one in a million people. CJD is still something of a scientific puzzle because it's always fatal, there are no treatments and it doesn't involve a bacteria or a virus, but a protein called a prion, which causes the brain to degenerate rapidly.
Tess Millet hopes her mother's story will raise awareness and perhaps mean an easier diagnosis, maybe even a cure, for patients in the future.
"They don't know how you get it. Some say it just happens. Some say it's an exposure. But until we know, we won't know how to prevent it," she said.