It takes Peter Interdonato 30 minutes to mix the IV cocktail of drugs his son must have every six hours: hydralazine to control his blood pressure, Reglan to help him digest, methadone for pain. Then, a separate tube of multivitamin supplements.

Michael is 21, with the body of a child and the energy of an old man. He is 5 feet 6 inches tall and his weight fluctuates between 85 and 100 pounds. Except for some occasional Chex mix and half-a-bowl of ice cream, he can eat no solid food. His drooping eyelids make him look tired, even in the rare moments when he is not. Rising from his wheelchair leaves him sweating and out of breath in minutes.

He has given up his job at the Mazza Gallerie movie theater in Northwest Washington. He has given up driving his Jeep Grand Cherokee. He has given up hockey, soccer and baseball. He has given up eating at his favorite fast-food chains, Chipotle and Chick-fil-A. He has given up video games, as well as writing fiction.

What has ravaged Michael has a name that can barely be wrestled into submission: mitochondrial neurogastrointestinal encephalomyopathy, or MNGIE, an exceedingly rare genetic disorder that destroys nerves, intestines, the stomach, muscles, even the brain. There is no cure. The average age of onset is 18. The average age of death is 38. The gastrointestinal problems leave many patients so emaciated that they can't fight off infections.

Unlike others with serious illnesses, Michael is essentially cut off from those similarly afflicted. MNGIE has been diagnosed in fewer than 100 people worldwide. The National Organization for Rare Disorders, a nonprofit health agency based in Connecticut, defines a rare or "orphan" disease as one that affects fewer than 200,000 people in the United States.

There are days when the isolation wears on Michael, a 2002 graduate of Bethesda-Chevy Chase High School. "It would make the situation a lot different," he said. "With other disorders, there are people you can talk to. . . . I probably won't meet anyone that has it."

Photographs from the days before he fell ill show a skinny but athletic youth with dark, wavy hair, a furry goatee and a large smile. His hair is more tousled now, his speech slower, his shoulders slouched.

With few others to turn to, his family has formed its own grass-roots campaign to save him. His 17-year-old sister Danielle, an aspiring comic book illustrator who graduated from Bethesda-Chevy Chase last week, maintains a Web site about Michael that has brought in almost $28,000 in donations to help pay for his health care.

MNGIE is passed down to a child from a mother and father who each have a mutated gene deficient in an enzyme responsible for regulating molecules known as thymidine and deoxyuridine. Doctors believe that when present in high levels in blood, these molecules can damage mitochondrial DNA, genetic material inherited from the mother. When damaged, it cannot produce proteins that provide energy to the body.

A Possible Cure

Peter Interdonato and his wife, Marie-Cecile, had no idea that they each carried the mutated gene. The chances that two carriers would meet and marry are extraordinarily slim, doctors said. But it meant that Michael had a one-in-four chance of getting the disease.

Danielle, who is approaching the average age of onset, faces the same odds as her brother. Doctors believe she will not develop the disease, but her parents said they haven't had her screened.

"It's not something we really want to entertain right now," Peter said. "Call us chicken. We can only deal with one sick child at a time."

Doctors have tried giving Michael an infusion of platelets without the enzyme deficiency on some MNGIE patients, which helped temporarily. Now, they believe replacing the bone marrow that produces the defective platelets could be a cure.

No MNGIE patient has tried a bone marrow transplant. After months of wrangling, the Interdonatos recently persuaded their insurance carrier, Empire Blue Cross/Blue Shield, to approve the procedure, which will cost about $200,000.

There's no certainty that it will work. "The only proof will be the first patient," said Charles Hesdorffer, professor of clinical medicine and surgery at Columbia University.

Because no one in the family had bone marrow that matched Michael's, doctors will instead use umbilical cord blood. The operation could take place as soon as this month.

"There aren't really other options," said Peter Interdonato, 58, a professor of graphic communications at the University of the District of Columbia. "This is really his only opportunity. The disease is threatening, it's progressive, it's not going to get better."

"I respect Michael's choice," said Marie-Cecile, 52, a part-time florist. "He's 21 years old, and he doesn't want to live the way he's living."

No Holding Back

Michael woke up about 9:30 on the morning of Aug. 23, 2002, one of the last carefree summer days before the beginning of college.

He never dated much -- he was a bit shy -- and felt more comfortable hanging out at his house with buddies, playing Nintendo or watching DVDs. That morning, he showered and dressed for an afternoon of Nintendo with a friend. As he slipped a sock onto his right foot, he noticed his big toe hanging limp. He could not move it.

Perhaps he had put his ice skates on too tightly the day before, his mother told him. Maybe he had a pinched nerve from playing so much hockey, his father said.

Michael thought it was odd, but he was more concerned about getting to his friend's house on time. He figured it would go away. "It was kind of a drag that day because it was all I could think of."

By October, his other big toe was limp. By summer 2003, he had lost most of the feeling in both feet.

"You could touch his feet and he wouldn't know it," Peter said.

In February 2004, he started vomiting almost everything he ate. Last September, his thumbs weakened, followed by his hands. After a few semesters at University of Maryland at College Park, he reluctantly went on medical leave.

"After you graduate high school and you're about to go to college, it's your first chance to be independent," Michael said. "It was kind of taken away from me before it got started."

The first few doctors who treated him at Children's Hospital and Johns Hopkins University Medical Center misdiagnosed another neurological disorder. Not surprising, said Michio Hirano, a leading expert on MNGIE who teaches at Columbia University Medical Center in New York. The disease is relatively new, he said. The first patients were identified in Japan in 1976.

These days, Michael rarely leaves his house, unless it is to see a doctor or physical therapist. After he became ill, he began spending most of his time in his second-floor bedroom, surrounded by the dozens of 4- and 12-inch Star Wars action figures he has collected. When he wants to go downstairs, his father carries him. When he wants to leave the house, his father puts his IV bag in a backpack.

While video games are not possible now, Michael keeps buying them, leaving them unwrapped on his desk, a reminder of what he has to look forward to.

And once in a while, he and his father go to the Game Parlor, a Chantilly video game store, to play the "Lord of the Rings" trading cards game, another one of his hobbies. His father holds the cards.

On a recent night, Peter shuffled the cards, each with characters and scenes from the films. He dealt a hand of eight cards. Michael sat in his wheelchair, wearing his usual outfit -- a navy blue T-shirt, black running pants and gray thermal socks. He looked at the cards in his father's hands.

"Okay Michael, no holding back on me," said his friend and opponent Scott Valentine.

Michael didn't hold back. Instead, his voice got louder as he gave his father commands.

"Play those two," Michael told him.

Every few minutes, Michael barked another order. His goal was to kill Valentine's fellowship, a set of good characters. "Play the small hope." "Play army with a polearm." "Reconcile," he said, ending one string of movements.

Forty-five minutes later, Valentine was on the brink of losing. He dropped his cards.

"I'm dead," Valentine said.

But the game wasn't over, and Michael was not about to let him give up.

"Let's just play it out," he said.

Physical therapist Shweta Shukla works with Michael Interdonato at a therapy session in Rockville.Michael at his 2002 graduation from Bethesda-Chevy Chase High School with parents Marie-Cecile and Peter.Michael Interdonato is lifted into the family car by his father, Peter, after a particularly taxing physical therapy session.Michael is all smiles after winning a fantasy card game against friend Greg Anderson, right, during a game in Gaithersburg. Peter holds the cards, but Michael calls the shots. Peter readies one of the various injections that he administers to Michael.