Doctors cure St. Louis boy's MSUD with liver transplant

MSUD is caused by the lack of an enzyme that breaks down some amino acids.

By Eva Dou

Published Feb. 23, 2009

At 7:30 a.m. on Feb. 3, 11-year-old Austin Sprock was on the operation table to receive a new liver.

It was less than 18 hours since he even knew he was on the waiting list.

The boy from High Ridge had received high priority because he had a rare condition, maple syrup urine disease, which prevented his body from properly processing protein.

MSUD is caused by the lack of an enzyme that breaks down certain types of amino acids, causing a toxic buildup in the bloodstream. The name comes from the sweet-smelling urine of infants with the disease.

Before last week, Austin could not eat meat, dairy, eggs, bread or a range of other foods. All his food was measured with a scale to make sure he did not exceed his protein limit for the day. He ate potatoes at every meal.

"I got really sick of them," Austin said.

A liver transplant is the only known cure for MSUD, but the risks scared Austin's parents from seeking the procedure until this winter, as his sicknesses grew more frequent and severe. A simple cold could touch it off.

"Over Christmas, Austin was extremely, extremely ill, almost to seizure level," mother Tina Sprock said. "We just couldn't do it anymore. We were afraid that one illness could cause permanent damage."

Austin wanted the operation. He just wanted to be able to eat normally.

His new liver gave him the enzymes to break down the branched-chain amino acids leucine, isoleucine and valine.

Upon his return home from St. Louis Children's Hospital, he ate his first ever piece of meat, a breakfast sausage.

"It tasted good," Austin said, speaking lethargically through the phone Sunday.

Tina Sprock said her son is recovering but has yet to regain his strength.

Post-surgery, he gets blood drawn twice a week from a central IV line in his chest, so doctors can check that there are no infections. Tina Sprock said Austin has gotten his blood drawn close to 700 times.

Austin is on heavy doses of immunosuppressant drugs to prevent his body from rejecting the new liver.

Tina Sprock said the 10 pills each morning and nine each evening can take him an hour to swallow. He doesn't like pills.

"It's hard," Austin said.

There won't be so many pills in coming months. After three months, most liver transplant patients are on only a couple different medicines, and by the end of a year, only one medicine, said Jeff Lowell, chief of Abdominal Organ Transplant at St. Louis Children's Hospital, who performed Austin's transplant.

Lowell said the transplant itself went perfectly, although Austin's sensitivity to the immunosuppressant drugs caused some problems with his kidney shortly after transplant. The dose was lowered, and the kidney quickly returned to normal.

"It's not uncommon that we have to fine tune things immediately afterward," Lowell said.

MU researchers have been studying MSUD in recent years.

Central Missouri's Mennonite community, which has a much higher rate of MSUD than the general population, has gained the attention of MU biochemistry professor Charlotte Phillips.

In 2007, Phillips did infant MSUD testing in the community using a cheek swab method that yields results in four hours.

MSUD occurs in one out of 225,000 live births in the general population, but the state's Mennonite community has rates of one in 150 live births, Phillips said.

Fast testing is crucial when it comes to a disease that can kill infants in two to three weeks.

Austin, like many babies with MSUD, went undiagnosed until he started having seizures and other serious symptoms.

"Formulas like Similac and Enfamil are actually killing them because they high in protein," Tina Sprock said.

During his first two weeks, she noticed he would have "startles" -- which a physician identified as seizures during an office visit.

Fortunately for Austin, the diagnosis was made before serious neurological damage took place.

Neither Tina Sprock nor her husband Billy has a family history of MSUD, but her son having the disease means both of them are carriers.

Austin has a seven-year-old sister, Cassidy, who does not have MSUD.

For now, Austin goal is to become a professional baseball player.

He's been sharpening his skills as second baseman and catcher for the Cobras at the Fenton Athletic Association.

Tina Sprock remembers that a bright spot during one of her son's many hospital stays was when St. Louis Cardinals pitcher Kyle McClellan made a surprise appearance at the hospital last summer.

"Austin immediately started badgering him with statistics," Tina Sprock said. "'You really are a Cardinal's fan,' Kyle McClellan told him. Austin got a shirt signed and we put it in a shadow box along with an autographed picture."

Because of the disease, Austin used to get tired and overheated quickly during games. Tina Sprock said she hopes the transplant will help her son pursue his dreams.

"He can play a double header baseball game, and I won't be worried and have to pull him out of the game," Tina Sprock said. "He can run himself ragged. He can be a boy. We're so excited."