Texas Girl, 12, Who Is Always Hungry, to Get Gastric Bypass

The removal of a benign brain tumor affected Alexis Shapiro's appetite.

March 21, 2014— -- A Texas girl will get gastric bypass after the removal of a benign brain tumor left her always feeling hungry.

Alexis Shapiro, 12, suffers from a rare condition called hypothalamic obesity where she constantly feels hungry no matter how much she eats.

The symptoms started in 2011 after the removal of a benign brain tumor resulted in damage to Alexis' pituitary gland and an area in the hypothalamus part of her brain that affects how her body perceives signals from her digestive system.

According to Alexis’ mother, Jenny Shapiro, the 12-year-old has gained on average two pounds every week since her surgery two and half years ago. Before the surgery Alexis was 51 pounds, as of December she weighed 140 pounds according to her mother.

“I started to lose hope that we would find a way to control her weight gain. Each day it seemed like there was something new that was hurting Alexis or she’d discovered something else she could no longer do,” Shapiro wrote in a blog for the Cincinnati Children's Hospital Medical Center.

In an effort to help Alexis lose weight, doctors at the Cincinnati Children's Hospital Medical Center will perform the gastric bypass surgery Friday morning.

Dr. Thomas Inge, a surgeon and professor of surgery and pediatrics at Cincinnati Children's Hospital Medical Center in Ohio, is treating Alexis. Inge said when damage is done to the basal medial hypothalamus it can wreak havoc on the patent's metabolic system.

Shapiro said Alexis’ energy level has also suffered after she was diagnosed with hypothalamic obesity.

"She doesn't have any adrenaline either. She runs on low often," Shapiro told ABCNews.com in an earlier interview. "She can't keep up for a whole day without taking a nap."

In addition to the bypass surgery, part of Alexis’ vagus nerve will be removed. The nerve is thought to transmit powerful signals from the brain to the pancreas that can lead to feeling of always being hungry.

"I'll say from the start, is we don't have enough research on the topic and we're trying to bring more understanding on how gastric bypass can work," said Inge. "What the gastric bypass seems to do is to trick the brain that those hunger signals are not really [there.]"

There is a chance that the surgery may not work for Alexis. It is a fact that Shapiro had to explain carefully to her daughter.

"She is also very excited and she wants to do it. [We explained] it's going to be hard and it's going to be hard after the surgery but she might get her life back," said Shapiro. "She said that she's no worse off than she is now. She can't do anything now so why not try something different."