To shed light on an unthinkable, largely unknown childhood disease, marathon runner Tim Borland is planning to do the unimaginable.

Borland, an ultra-runner and trainer, plans to run 63 marathons in 63 days. Since beginning Sept. 3 in Anaheim as part of a Disneyland run, he has run 26.2 miles a day and plans to continue the pace until Nov. 4, when he will attempt one last marathon run in New York City.

Borland, 31, has scheduled his runs in cities where at least one resident is afflicted with ataxia-telangiectasia (A-T), a rare, fatal genetic disease that affects children.

On Sept. 12, he plans to run a full marathon in Escondido, home of A-T patient Sarah Shaw, 7.

"I'm definitely inspired by those kids," Borland said about the children he has met who have A-T.

In the playroom at her Escondido home, Sarah was a bit unstable as she picked up a doll and teased the family's new puppy. Her mother, Elizabeth Shaw, held Sarah's hand as her daughter stood, then wiped from the child's mouth a bit of drool, one more reminder of the disease that is slowly attacking her body.

"It's a difficult stage for me," Shaw said. "She's declined over the summer. Her speech is slow. It's more difficult for her to enunciate."

Sarah is one of about 500 people in the United States with A-T, although there likely are more because the disease is little known and its symptoms often are mistaken for other conditions.

A-T is a progressive, degenerative disease that attacks several of the body's systems. Signs of the disease, such as a loss of muscle control, appear around age 2. Children usually need to use wheelchairs by age 10, and it becomes difficult for them to read, speak and eat as the disease progresses.

About 25 percent of people with A-T develop a treatable type of cancer, mostly lymphoma and leukemia, which strikes a specific type of white blood cell called the lymphocyte. About 70 percent of children with A-T also have an immune deficiency that leads to respiratory infections that sometimes become life-threatening.

To boost her immunity temporarily against disease, Sarah receives regular injections of gamma globulin, a protein containing antibodies that her body does not produce.

A-T also can cause type-1 diabetes, premature gray hair, difficulty swallowing and slowed growth. Children with A-T often do not live past their teen years.

Shaw said her daughter was diagnosed with A-T at about 18 months old.

"I think when you get such a diagnosis, your world pretty much comes to an end as you know it," said Shaw, who also has two sons, ages 4 and 9. "At that point, my life unraveled and I wasn't able to deal with the reality of what was ahead. After that, I slowly got back into my own sense. There's nothing to do but persevere and make her life as fun and fulfilling as can be."

Children with A-T are alert and intelligent, although their movements are slowed and their ability to communicate hindered.

Shaw said her doctors did not know what was wrong with Sarah at first. Coming from a family in the medical field and having worked for a pharmaceutical company, Shaw was on familiar ground when she began asking questions about the disease.

"I didn't sit around," she said. "I attacked this thing. I did research. I talked to my dad, my brother, friends. What can be done?"

Shaw learned there was only a handful of diseases that could be affecting Sarah. After visiting a neurologist and an ear, nose and throat specialist about her daughter's wobbly walk and finding no reason for her imbalance, the causes for her condition grew more narrow.

Finally, a specialist at UCLA tested for a protein elevation that would confirm A-T, but by then Shaw said she already knew.

Because the disease is so rare, Shaw could not find any other local families who were affected by it. Instead, she found an online community of family members who share stories about their children.

"We can converse with each other and give information," she said. "You don't feel so disconnected and alone with this rare disease."

With no cure or treatment for the disease, Shaw focused on raising awareness of A-T so other families might be able to detect whether their own children have it. She also hopes a greater awareness of the disease will bring additional funding for research, which is still very preliminary.

The responsible gene for A-T, ataxia-telangiectasia mutated, was discovered just 12 years ago. The protein is part of a signaling system that is activated when DNA has been damaged. With the protein itself damaged, the signal to repair the DNA does not get through, causing a degenerative condition.

"This is a slow, progressive and cruel disease," Shaw said.

At 7, Sarah does not yet know what is happening to her, although she is beginning to realize she is different.

After watching other children in a gymnastics class, Sarah told her mother that she can't do the things other girls can do, and she has asked why she has to go to the lab once a month for injections.

"I have to talk about it in very gentle terms with her," Shaw said. "We have chosen not to talk about something that's difficult to understand."

At a kickoff ceremony for Borland's run at Disneyland on Labor Day weekend, Shaw said, organizers announced $450,000 had been raised to research the disease. Ben Affleck, who met an A-T patient while filming a movie, is the celebrity spokesman for the cause.

Borland, a Los Gatos resident, became involved after learning that his friend Jim Achilles' 16-year-old daughter, Cathryn, had the disease.

On Sept. 12, his run will begin at the Lake Hodges recreation area at about 1 p.m. Up to 15 people who contribute $150 can run the entire 26.2-mile trek around Escondido with him. Others can join him in the final stretch for a 3K fun run as part of the $25 donation to participate in the picnic. That begins at 5 p.m. on Lake Drive across the street from the Del Dios Country Store, 20154 Lake Drive.

Borland has run about 20 marathons and has branched out to ultra-events, including a 24-hour adventure race.

He's never done anything as challenging as 63 marathons in a row, but said other runners have pushed their abilities to the extreme. A young athlete with one leg ran 3,400 miles across Canada in the 1980s, he said, and an 8-year-old girl in China once ran 40 miles a day for almost two months.

"We have no interest in trying to break records, set records or trying to compete with anybody," Borland said. "We're strictly about raising money and raising awareness."

To prepare for the run, Borland said he was tested by a Stanford University doctor who determined that his body runs on 70 percent carbohydrates, 20 percent protein and 10 percent fat, which will help him tailor a daily diet of 8,000 calories to best fuel his system.

Borland also will wear a harness to measure his vital statistics for a Stanford study, and he sometimes will push a jogging stroller to draw attention to the cause. Sometimes the stroller will carry an A-T child, and sometimes it will be empty in memory of children who have died from the disease.

Borland's wife, Michelle, and their two young children will travel with him between cities in a recreational vehicle that will promote the run.

For more on the run, call Shaw at (760) 484-1723 or visit www.ATCP.org. People can register for the picnic at the event or by sending a $25 check, payable to ATCP Children's Project, to the AT Cure Tour-Shaw, 3120 Bernardo Lane, Escondido, CA 92029.

Contact staff writer Gary Warth at (760) 740-5410 or gwarth@nctimes.com.

Marathon/Fun Run/Picnic for ataxia-telangiectasia

When: 5 p.m. Sept. 12

Where: Lake Hodges recreation area, across the street from Del Dios Country Store, 20154 Lake Drive at Lake Hodges, Escondido

Cost: $25 for picnic and fun run, $150 for full marathon

To register and for information on A-T, visit the Web site www.atcp.org.

Direct link to register: www.communityatcp.org/NETCOMMUNITY/Page.aspx?&pid=369&srcid=198&frtid=8

For information on the event, call Elizabeth Shaw at (760) 484-1723.