That familiar sense of life zooming by too fast is what makes progeria so compelling for the rest of us. But a disease that affects no more than 15 or 20 Americans at any one time would barely get any research attention if not for an advocate to promote it. Scientists make choices, and politicians make financing decisions, based on the likely payoff; the more common the disease, the greater the chance that there will be government grants available to support it and scientists who want to do the work. How, then, does a disease this rare become the object of study?

That's where Sam Berns's mother comes in. The woman who offered those warm cinnamon muffins for Sam's breakfast is herself a physician-scientist, and she has devoted the last six and a half years of her life to searching for a cure for her son's disease. Since the day in 1998 when Sam's condition was diagnosed, his mother, Dr. Leslie Gordon, has marched to the cruel allegro of her son's illness, which she knew could kill him by the time he reached his teens. She redirected her career, quitting her internship in pediatrics in order to devote herself full time to progeria. She created a nonprofit organization to promote research into the cause and possible treatments and cures. After spending months reading scientific literature, she eventually talked her way into the laboratory of a cell biologist at Tufts University, soon learning enough from him to start her own progeria-research lab. She co-sponsored three major conferences with the help of the National Institutes of Health. She shuttled to Washington to lobby on Capitol Hill, resulting in a legislative coup -- specific mention in the Children's Health Act of 2000 -- that forced N.I.H. to conduct and support progeria research. And in the spring of 2003, she stood alongside two of the nation's leading geneticists to announce the discovery of the progeria gene.

The attention Gordon has generated has been remarkable. From her unique position as both mother and scientist, she has assembled a powerful group of collaborators to push this rare disease to the front of the research agenda. The most zealous among them, of course, is Gordon herself; she has the most to lose. Gordon is motivated by a simple, fierce and ancient passion: the relentless drive of a mother to save her child. The others are motivated by something more complex. On one hand, they're driven by their heads, captivated by the scientific questions they can answer by studying progeria, as well as by the tantalizing possibility that they might learn something about aging itself. On the other hand, they're driven by their hearts in much the same way Gordon is. They want to rescue children who are intelligent, endearing and doomed. You might have heard of progeria. It's known as a disease of accelerated aging, causing children to become withered and wattled and to die of heart attack or stroke at an average age of 13. It first came to general attention in 1981, when the Pulitzer Prize-winning photographer Eddie Adams took a picture of two boys with progeria, Fransie Geringer of South Africa and Mickey Hays of Texas. Craggy-faced and bald under their baseball caps, the boys met in Disneyland, where Fransie was sent by a wish-granting philanthropy called the Sunshine Foundation. The photo was carried on Associated Press wires nationwide and appeared on the front page of the Style section of The Washington Post under the headline "Growing Up Old."

The headline, and our conventional understanding of progeria, did not have it exactly right. The children are not quite "growing up old" -- the disease is not one of being older than their chronological age as much as looking older. But the looks are what resonate. Who among us hasn't felt the strange disconnect between his own internal clock -- mine is set permanently at age 19 -- and the craggy, lined face that surprises him in the mirror? With progeria, this disconnect is more than just disorienting; it's a death sentence.

Children with progeria have wrinkles and age spots, and they're usually bald. They are extremely skinny, and they grow no taller than three or four feet. They never mature sexually, have almost no shoulders and usually have arthritis; their hips tend to lock in a position called a "horse-riding stance." Their faces, disproportionately small for their head size, are odd: beaky noses, prominent eyes, misaligned teeth in shrunken mouths.