When morning arrives in the DeYoung household in Murrysville, it sets off what Joan DeYoung calls "a symphony of motion."

As with any family, the DeYoungs must get out of bed, shower, dress, eat and go to work or school.

But in the case of Joan DeYoung's sons, Henry, 23, and Andrew, 21, all of this takes much longer than normal because they both have a muscle-weakening disorder known as spinal muscular atrophy, which makes it impossible for them to stand, walk, feed themselves, type or do any of the million other quotidian tasks most of us take for granted.

Both are brilliant students at Carnegie Mellon University. Henry is starting a doctoral program in computer science and was the school's top undergraduate in computer science last spring. Andrew is a fourth-year student majoring in chemistry.

They spend many of their waking hours in front of computers, but just getting them there takes the symphony that Mrs. DeYoung must orchestrate.

The first challenge is to get each young man onto the wheeled therapy tables that were custom-built by their father, David, an Alcoa research engineer. To do that, she employs a Hoyer lift, a metal frame with a sling that she uses to hoist her sons from their beds onto the tables, and later, from the tables into their motorized wheelchairs.

They then take the first of two daily treatments with a nebulizer, which bathes their airways with a medicated mist that eases their breathing.

The most dangerous aspect of spinal muscular atrophy is weakness of the chest muscles and diaphragm, which makes it hard for those with the disorder to cough and clear their lungs of infections.

Both Henry and Andrew have spent time in the hospital with serious chest infections. As Henry put it, "It's not so much that I have extra vulnerability, but when I do get sick, it's harder to get rid of the cold."

"Sometimes I've even been in the hospital for respiratory things," Andrew said, "and I was pretty close to being called by the Lord." One time, only his mother's intervention, pushing on his chest, kept him from choking to death.

So the morning and nighttime breathing treatments are vital, Mrs. DeYoung said.

As an extra precaution, they also don electrically powered vibrating vests -- the same kind used by cystic fibrosis patients -- which help shake loose secretions in the lungs so germs won't settle there.

Another feature of SMA is spinal curvature, so the next step in the morning routine is for Henry and Andrew to put on body braces beneath their clothes so they can sit up in their wheelchairs.

Even with the braces, though, they can only remain in a sitting position for a limited time, Henry said. The brace, he said, "fits pretty good, but it doesn't fit so good if I'm up for more than six hours."

Even when they are sitting, they are never still. The motors on their chairs frequently whine into action as they shift the position of the backrests to avoid pressure sores.

As a final aid to their lungs, they also wear BIPAP breathing tubes, which snake over their heads to their nostrils and are held in place with straps. The acronym stands for bi-level positive air pressure, which means pressurized air flows into their noses when they inhale, but the pressure then decreases to make it easier for them to exhale.

For most of the brothers' lives, Joan and David DeYoung handled these daily chores themselves. Once their sons reached high school, though, the family began to rely more on volunteers from their congregation, Murrysville Community Church, and on students and nurses.

One of the volunteers is Irene Winkler, who has known the DeYoungs since before the boys were born. Like many of the community aides, she is there primarily to help them complete their demanding schoolwork, which poses challenges of its own.

Both Henry and Andrew can make limited use of a computer mouse, sometimes calling up an on-screen keyboard to type papers that way. For the highly technical scientific papers and homework each must do, though, it's easier to dictate to volunteer typists.

While using the on-screen keyboard is laborious, dictating is a lot of work, too, Ms. Winkler said.

"I typed a lot for Henry for his computer programming course," she said, "and he has to say things like 'open brace, closed brace,' or 'open bracket, closed bracket,' so when there's some English sentences, I love that. We may work for four hours on the same problem and it's not necessarily finished by then."

While both Andrew and Henry are full-time students at Carnegie Mellon, they are not often on campus, partly because of their limited tolerance for staying in the wheelchairs, and partly because of the risk of picking up germs.

To accommodate them, the school videotapes most of their lectures and webcasts them so the brothers can watch them at home on their computers. They often attend the smaller discussion classes known as recitations, but the school has been flexible in helping them schedule those visits.

The arrangements have been a learning process for both Carnegie Mellon and the family, David DeYoung said, but the tone was set early on by computer science professor Mark Stehlik.

When Dr. Stehlik was presented with the challenge of how Henry would be able to go to school there, Dr. DeYoung said, "His response was: Yeah, so we've got a kid who got these top grades in high school and has so many AP credits and he wants to learn -- why not? Let's let him learn."

When the chemistry department required Andrew to attend laboratory sessions, it gave him a graduate student to do the physical work in the lab, but also made sure that the student didn't do anything without getting instructions from Andrew first.

"Even when I had to use a burette" -- a glass measuring tube -- "I would have to look at it and say, 'OK, how about adding two more drops,' " Andrew recalled.

While they use a whole cadre of people to type their schoolwork, "I think Carnegie Mellon knows there's no academic help coming from home, that's for sure," said Mrs. DeYoung with a laugh.

David DeYoung agreed. When Henry took an initial calculus class at Carnegie Mellon, he asked his father, who is a metallurgical engineer, to help him with some of the axioms.

"This one problem, all weekend I thought about it," Dr. DeYoung said, "and I'd have the problem on the dresser when I got up in the morning, and I think by Monday I'd figured out the answer to that one problem, and I said to Henry, 'You're on your own from now on. I'm going to be of absolutely no help to you.' "

When the boys were first diagnosed with SMA, Dr. DeYoung said, " I remember the neurologist said these kids with SMA tend to be brighter than average."

But Arthur Burghes, a noted SMA researcher at Ohio State University, said that notion came from older studies, and today, "I think most experts would say it's debatable whether their intelligence in general is higher than the general population."

SMA patients do tend to be articulate and do well in school, though, he added, partly because "if you cannot move around very quickly, you're likely to concentrate a lot more on the books."

Both brothers are interested in research careers, but when it comes to the future, they are acutely aware of how little they control.

"I guess it's mostly the same as for anyone else," Henry said. "You just have to trust that God has a plan for you and try to live each day with what he gives you that day."

Thinking back to last year's Minneapolis bridge collapse, Andrew put it this way:

"I'd like to try to live how God wants me to live, and live for his glory and not mine, because you don't know when the bridge is going to collapse under you when you're driving to work.

"I enjoy what I am studying, and I am so, so blessed to have extraordinary and loving parents.

"Many, many, many, many folks with SMA and other neuromuscular conditions do not have the opportunity to go to college. Most probably live in group homes.

"Henry and I are just so, so blessed to have the loving parents that we do."