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Alexis Shapiro, the Texas 12-year-old whose rare condition caused her to balloon to 203 pounds even while feeling constantly hungry, will finally get the life-saving surgery she's been waiting for today.

Shapiro gained widespread attention last year when her family's insurance company refused to pay for gastric bypass surgery because she was so young; the family raised enough money to pay for the doctor-recommended procedure, but the insurance company ended up reversing its decision.

Now that the surgery is at hand, "She’s nervous," mom Jenny tells NBC News. "Excited, but nervous. The last time she had surgery, her life totally changed." It was a 2011 brain surgery that messed with Shapiro's metabolism, leaving her with hypothalamic obesity and panhypopituitarism.

She would continue to gain about 2 pounds each week without this morning's surgery, with her weight going as high as 400 pounds, according to the pediatric obesity expert who will lead the operation.

In addition to her stomach being made smaller, part of her vagus nerve will be snipped; that should help her to feel full after eating and to get more control over her appetite.

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The obesity expert predicts she'll lose about 40 pounds in the first year, but isn't sure she'll ever get back to "normal" and says she will likely always have to monitor her diet and exercise.

Because of the interest in Shapiro's case, Cincinnati Children's Hospital will live-tweet the operation here. Why? "We wanted to be sure we didn’t have a ton of media on site," a hospital rep tells the Cincinnati Business Courier.

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