“This is what we’re really all about at N.I.H.,” says Gahl, a compact 58-year-old who tends to make dry jokes in his slightly gruff baritone about almost everything — except science. “We’re in this business because we want to define and understand new diseases.” The expectation is that this work will offer important insights into the mechanisms of more common, more familiar diseases too. But knowledge can be double-edged: useful for the community at large, yes, and in some cases even helpful for the patient, but often incomplete, confusing or unbearably grim. Gahl worries constantly about taking away from his patients their last refuge: hope. When you’re suffering from a nameless malady, it’s easy to think that the only thing standing between you and a cure is the name itself.

The limitation of knowledge is something that troubles Gahl — or would trouble him if he allowed himself to dwell on it. Gahl has been at the N.I.H. for his entire career. He was born in a small town in Wisconsin, studied biochemistry as an undergraduate at M.I.T. and received his medical degree from the University of Wisconsin-Madison, where he also did his pediatrics residency and went on to earn a Ph.D. in oncology research. When he first arrived at the N.I.H. in 1981, it was as a fellow in the new field of medical genetics, back when scientists felt they were on the threshold of the era of gene therapy, when all you would need to do to cure a disease would be to find its gene, figure out what the gene did and imitate it. The ensuing years have shown how difficult it is to bridge the gap between the gene and the cure, which has been accomplished far less often than people once predicted. Despite the accumulating disappointments and false starts in genomic medicine, however, Gahl has never given up searching for the genetic bull’s-eye.

As he described Summer Stiers to me for the first time in October, Gahl sounded like a mixture of teacher, scientist, enthusiast and old-fashioned healer. “It looks like she has leaky membranes; what causes that?” he began, as though he were a senior attending physician and I were a medical student on rounds. “She had a diagnosis as a child of Coats disease, where fluid leaks out of her eye, and then there’s a reaction; her eye was removed. Her kidneys are ruined; her gut is problematic, she had bleeding; her lungs are reasonably O.K.; she’s got calcification in her skin; her vessels leak.” Gahl was certain he would accept her into the program. “This is an absolutely great case,” he said. It had everything he was looking for when he first helped design the program: documentation of her long, perplexing history and the likelihood that she was suffering from something entirely new. He was also impressed with the patient’s good disposition and coping mechanisms, which at the time he knew about only because of how Robert Pinnick, her primary-care physician, described her in his introductory letter. “We appreciate your interest in helping us make a diagnosis in this wonderful 31-year-old woman,” Pinnick wrote, “whose indomitable will to survive and always positive and pleasant attitude make her case not only tragic, but intriguing and a joy to pursue.”

There was fierce competition among patients for a spot in the Undiagnosed Diseases Program, which began as a $280,000 pilot initiative last May. (It was later approved for full financing — $1.9 million for fiscal year 2009.) By the time Gahl showed me Stiers’s case files in his cramped, chilly office that October afternoon, he had received more than 1,000 inquiries. He was in the process of reviewing about 300 charts and had accepted 35 patients. Another 100 or so charts were circulating through the N.I.H. for review by relevant specialists, and Gahl expected that another 20 patients would be admitted to the program before the end of the year. Summer Stiers, as Gahl anticipated, turned out to be one of them.

Image Credit... Katherine Wolkoff for The New York Times

When I first spoke with Stiers by telephone in mid-November, I could tell what it was about her that captivated Gahl. She was soft-spoken, with a lilting, little-girl voice, and even when she was telling me about the devastating series of physical breakdowns that have afflicted her, there was nothing complaining or self-pitying about it. Only once did she give a hint of her frustration, when she mentioned being told earlier that day that her phosphorus numbers were high, always a concern on dialysis. “They don’t know why it is, since I’m doing everything they tell me to do; I’m eating just what they tell me to,” she said. “That’s kind of what my whole life is. I follow directions — I’m a good little follower, I do what I’m told — and this happens anyway.”

Stiers was born in 1977 in Portland, Ore. She had a troubled childhood: her father left before she was born, and she remembers her mother as a distant, difficult parent. The first sign of Stiers’s health problems was that her teeth were weird. They were odd, small and sort of pointy, and she was told there were no buds for permanent teeth behind most of her baby teeth. When she was 10, problems started with her right eye: a black mass in her central vision resulting in several futile operations, which led to pain and inflammation and eventually total blindness in that eye. Her condition was diagnosed as Coats disease, a rare eye disorder, though her symptoms were not at all typical. “They told me there was a lot of pressure,” she said, “and they tried to take care of it surgically, like they did back then, cutting little slits to let the pressure out.” The operations only bruised and battered her; the eye hurt constantly, the vision was destroyed and finally, on her 14th birthday, Stiers had her right eye removed. A year later she received a prosthetic eye. She’s now on her third prosthetic, and the color matches her own blue-gray eye color so perfectly that it’s hard to tell which one is real.