Patients with rare metabolic disorder get shot at eating cheeseburgers

Liver transplant offers patients a chance to consume high-protein foods that their bodies could not metabolize

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Nearly two years ago, a 4-year-old boy from Fairfax, Va., who had never tasted chocolate, ice cream or cake became the first patient at Children's Hospital to get a liver transplant to treat a rare inherited disorder called maple syrup urine disease, or MSUD.

Annie O'Neill, Post-Gazette
Amy Zimmerman, 21, just received a liver transplant to relieve her of her condition called maple syrup urine disease, a rare inherited metabolic condition.
Click photo for larger image.

Jakob Jasin, who nicknamed his donor liver "Tommy," was soon eating his first cheeseburger and Double Stuf Oreo cookies, instead of avoiding high-protein foods that his body could not metabolize.

Since then, another 10 MSUD patients, ranging in age from babies to young adults, who received liver transplants were also cured of the condition, in which an enzyme deficiency allows the buildup of toxins that can lead to neurological problems or death, said Dr. George Mazariegos, director of pediatric transplantation at Children's.

"We call it a clinical cure in that they no longer have to restrict their diet," he said. "The [donor] liver provides enough of the needed enzyme to correct the defect from a functional point of view."

The results of the first 11 transplants for MSUD, a protocol developed by experts at Children's and the Clinic for Special Children in Strasburg, Lancaster County, were reported in the American Journal of Transplantation.

MSUD is a very volatile condition, said Dr. Mazariegos, one of the study's authors.

"For many years, medical therapy was thought to be the best that could be done for this disease," he said. "We believe that for some patients transplant actually may be a better option."

People with MSUD lack an enzyme that breaks down certain amino acids, which are the building blocks of proteins. The accumulation of the amino acids gives the urine a characteristic burnt sugar smell. A child must inherit a copy of an abnormal gene from each parent to develop the condition.

Amy Zimmerman, 21, of Lancaster County, ate only fruits, certain vegetables and a tiny amount of grains until January, when she got her liver transplant.

She's had some complications, including an episode of rejection, and is currently hospitalized because of an infection.

"There's been times when I have thought maybe this wasn't worth it," Miss Zimmerman said. She's still adjusting to her broadened food horizons, after having it drilled into her that eating high-protein foods would make her sick.

"It's a matter of making my stomach believe my head [and] believe my heart," she explained. She figures that like a baby, she'll have to try a new food several times to acquire a taste for it.

"I love eating potatoes and finally I can eat more than one," Miss Zimmerman said. "I like eating my mom's chicken and rice."

Study patients had what's known as classic MSUD, meaning they had less than 5 percent of normal enzyme activity, Dr. Mazariegos said.

In addition to alleviating metabolic abnormalities, transplantation appears to improve some cognitive impairments, mood and behavior disturbances, and other neurological problems thought to be permanent.

"We weren't anticipating this," Dr. Mazariegos said.

All the patients received transplants of whole livers. It's possible that partial liver transplants would also be effective, which could make scarce organs available to more patients.

In fact, the livers of MSUD patients, which are otherwise healthy, could be transplanted into people who need them to treat a different disease, Dr. Mazariegos noted. The recipients would not get MSUD because their other organs and tissues would make enough of the missing enzyme to compensate.

One such "domino" transplant with an MSUD patient's liver has been done at another hospital, and Dr. Mazariegos plans to study the procedure here.

So far, 18 MSUD patients have been transplanted at Children's, he said.

Anita Srikameswaran can be reached at or 412-263-3858.


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