Mitochondrial disease picked the wrong guy. The genetic disorder that uses stealth to prey on its victims, terrorize concerned parents and baffle even the most highly trained doctors, has lodged itself into the cellular make-up of one Colby Wren. Bad move.

Wren, the son of Braves general manager Frank Wren and a sophomore first baseman on the Georgia Tech baseball team, is an outgoing, engaging 20-year-old who is not one to keep quiet.

This fairly common yet obscure disease might have wreaked havoc on his gastrointestinal system and forced him to quit high school football and still compromises the very muscles it takes to play the sport he loves most — baseball — but mitochondrial disease cannot touch his nerve.

It’s not going to shame him either. For the personable Wren, it’s no big deal to talk about his stomach problems, how he could probably vomit on command. He’ll openly describe how he was once so dehydrated from practicing football in the heat he hardly urinated for three days.

Wren identifies the point when he finally knew he wasn’t just a “chubby out-of-shape kid that threw up every day at football practice” after one last set of up-downs, when he blacked out, lost control of his body, and wet himself.

See, Wren knows there’s something much worse than plain-talk: It’s not knowing.

For more than two years, he had no real understanding of what was happening to his body and no doctor who could tell him.

It seemed the more he worked out, the worse shape he’d be in. If he started off bench pressing 185 pounds, he was down to 130 the next week. He’d have cramps that lasted two hours after a football game, no matter how much fluid he drank. The longer he played in a game — and as a ninth grader he played fullback, linebacker and kicked and punted for Landmark Christian’s junior-varsity team — the worse he got.

He once had to be carried off the field after going into a full-body cramp attempting a punt.

“I remember all the coaches were like ‘Never get carried off the field; crawl off if you have to,’” Wren said. “I would have if I could move my body.”

He didn’t know it, but he was dealing with a chameleon of a disease. It targets mitochondria, “power plants” in almost every kind of cell in the body which convert nutrients from food and oxygen into energy. Mitochondrial disease can affect different systems in the body — brain, heart, muscle — at different times in different people. It’s complex and difficult to diagnose.

Finally, an answer

Mitochondrial disease affects 1 in 3,000 people, yet it’s hardly recognized compared to some of its cousins such as ALS (Lou Gehrig’s), Alzheimer’s, autism, muscular dystrophy and Parkinson’s.

That’s why it took Wren a year-and-a-half and some 25 to 30 visits to different specialists before he was diagnosed. He saw a gastroenterologist, endocrinologist, neurologist, cardiologist and a nephrologist.

At first doctors thought diabetes, then cystic fibrosis. Wren himself wondered if he had a brain tumor, like the benign one his father had in his early 20s. His life was playing out like one long episode of “House,” one of his favorite TV shows, without the tidy ending.

Wren was scoped, scanned, and biopsied. “I could probably do an EKG myself,” he says. He was rushed into the emergency room within 20-25 minutes of finishing a football game, twice, so doctors could draw his blood when he was at his most fatigued.

Even then, tests were inconclusive.

“It’s a real frustrating process,” Frank Wren said. “I guess I’m your basic type-A. I think I can fix it. I want to fix it. And [my wife] Terri was the one living it day in and day out, trying to get him from one doctor to the next and get the results. We came up to one dead end after another.”

It finally came to a head the summer before Wren’s sophomore year in high school during “Hell Week.” On the second day of workouts at football camp in rural middle Georgia, he already was throwing up before the 6 a.m. practice started. Early on in practice, when it wasn’t that hot yet, he realized he had stopped sweating.

Trainers put Wren in an ice bath before heat stroke could set in. His father, who had come along to keep a close eye, drove him back to Atlanta. A frantic call to the neurologist, who then consulted Wren’s other doctors, brought word: Wren should see Dr. John Shoffner, a specialist in mitochondrial disease. He was world renown and practicing in Atlanta.

Three hours in Dr. Shoffner’s office and a white board helped finally crack the case. Shoffner wanted to know every symptom, every episode Wren had ever had. His mother consulted more than 100 pages of notes, a time line she kept, and test results. His father came on his lunch hour and left. Wren even dozed off at one point.

Shoffner had a suspicion it was mitochondrial disease. A muscle biopsy, which took months to process, confirmed the diagnosis.

“The entire time I just wanted to know what it was,” Wren said. “It wasn’t like something that hit me and I was depressed for a week. It was like ‘OK, cool, we know what it is now. Now what do I do?’”

Wren had to give up football, but his case was mild and could be managed with dietary supplements such as Coenzyme Q10, which he calls it the vomit shot. “Throw-up tastes better.”

Coping, with a purpose

But Wren knows he’s lucky. He can still play baseball at Tech with his twin brother Kyle and lead a normal life. Even Rocco Baldelli, the former Tampa Bay Rays outfielder who was diagnosed with mitochondrial disease about the time Wren was, had to quit baseball.

Wren’s father has good health insurance and immediate access to the Braves’ top-notch medical staff. He could pull strings to get his son in to see Shoffner after only six weeks, when his waiting list is up to a year-and-a-half.

Wren has a platform to help other families identify and cope with mitochondrial disease, not to mention the personality.

“He can meet a stranger and talk to anybody,” Terri Wren said. “It’s who he is.”

Wren’s dream isn’t to play major league baseball. He knows a grueling 162-game schedule is more than he could handle anyway. It’s to work for a team in public relations.

Wren keeps mitochondrial stats handy on his cellphone, for quick reference. His Twitter account is @mitoguyGT. He has recommended Shoffner to his girlfriend’s boss, whose child has mitochondrial disease.

Wren is an ambassador for the Foundation for Mitochondrial Medicine. He and his parents hosted the second annual “Hope Flies” gala Saturday night in Buckhead to raise both awareness and money to research treatments. There is no known cure, or even a very effective treatment, Shoffner says, but they raised $250,000 last year and hope for more of the same.

“Coenzyme Q10 just helps a little bit, decrease the chance of muscle breakdown,” Shoffner said. “The real point of emphasis is the research that’s going on right now into better treatments.”

Wren said there are mitochondrial patients who attended last year’s gala who have since died. His mind goes to his 5-year-old friend Zach, who wasn’t well enough to make the gala last year and died over the summer.

“If you met Zach you would think he was like 1 year old, and he was 5,” Wren said. “He was in the hospital every single day for almost his entire life. He got to come home and hang out with his older brother a little bit. He was a little spider monkey, a nice little kid; their family was as sweet as you could get. ...

“I’m probably not going to be 85, 90, but I’m not going to die at 25 or 30. I don’t have a ticking clock on my back like a lot of kids.”

Wren will keep pushing through as he always has. He can do something to help, and he knows it.

For more information on the disease, go to www.foundmm.org.