The latest medical mystery in the news is the story of a 21-year-old Texas college student with a disorder that makes her incapable of gaining weight. Reports that Lizzie Velasquez needs to eat every 15 minutes to survive are inaccurate, according to her father. She has a healthy appetite, he says, but does not eat as frequently as widely reported.

Velasquez, a Texas State University student, says on her website: “What the syndrome causes is that I'm not able to gain weight." She reportedly weighs around 60 pounds.

“I eat whatever I want all day long and just can't keep the pounds on,” she wrote on her site.

The condition is known as neonatal progeroid syndrome. There are about 45-50 reported cases worldwide. Neonatal progeroid syndrome is a type of lipodystrophy, a disorder characterized by a selective loss of body fat.

People with lipodystrophy cannot store fat.

“Whatever they are eating goes to the wrong place,” said Dr. Abhimanyu Garg at the University of Texas Southwestern Medical Center in Dallas. “If they eat enough to burn it by muscles, it’s fine. Usually, all of us, we eat extra fat, and it goes to our fat cells. When we are starving or exercising, the fat cells release energy, it’s burned by muscle. Here they don’t have that option. What happens is it goes to their liver or directly to the muscle and puts stress on them. It damages them.”

In severe cases, children are born without fat on their bodies and look very muscular, he said. Garg has seen Velasquez, as part of his research on neonatal progeroid syndrome, but did not have permission to speak about her case.

Velasquez was born 2 pounds and 10 ounces, according to her website. She said she was born so small her clothes were actually doll clothes from Toys "R" Us because those were the only garments that fit her. Watch a video on Velasquez.

The condition is also known as Wiedemann- Rautenstrauch Syndrome, is also characterized by accelerated aging and lipodystrophy from birth. Children can have severe growth and development problems, eye problems, and facial patterns and loss of fat from the face, extremities.

“They remain thin, the defect is they can’t put fat in their body,” Garg said. “Whatever it is, they cannot overcome that defect by overeating.”

The first reported case was in 1977, said Garg, who is researching this disorder.

Patients with NPS do not fit one profile. They don’t necessarily have to eat more frequently and much about the condition is still unknown, he said. Some children die very early in childhood, but not enough is known about average life expectancy, Garg said.

The children have been reported to die from lung complications such as pneumonia or infections. For reasons unknown, the condition also affects the eyes. Then there are the psychological consequences of the disorder.

“Some are told they have anorexia, but they are in fact eating well, but look like they have anorexia,” Garg said. “They’re thought to have AIDS and different disorders.”

Scientists are trying to figure out the genetic basis of the disease and identify the gene for NPS.

Velasquez wrote on her blog that she frequently gets asked whether she would ever change her appearance if she could.

“God made me the way I am for a reason and I would never change that,” she wrote. “I lead a normal life as much as possible and deal with the bumps in the road as they come along with my head held high and a smile on my face!”