BAYPORT - As Newsday will profile this Sunday, until the age of 4, Marisa Carney was growing up as a happy and healthy toddler. For the past year, however, the Bayport girl has been fighting for her life against a rare and life-threatening disease.

Marisa, 5, was diagnosed with rapid onset obesity with hypothalmic dysfunction, hypoventilation and autonomic dysregulation, known as ROHHAD. She is one of only about 75 cases worldwide.

Marisa's father, William, says he and his wife called all of the major hospitals on the East Coast, and no one had even heard of his daughter's illness.

"We're not fixing her, we're not curing her, we're not doing anything other than keeping her alive," says William Carney.

The Carneys have to write down everything the 5-year-old eats and drinks, and track her bodily functions.

Marisa has a heart condition, high cholesterol and is attached to a ventilator that breathes for her in case her brain suddenly shuts down.

"I'm always scared because you never know if that's the day something bad is going to happen," says Marisa's mother, Danielle.

The Carneys say they are focused on finding a cure for their daughter's condition, and believe that there is a happy ending to the story.

Marisa's story will be featured in a 16-page section this Sunday in Newsday. will also have a 10-minute mini-documentary on Marisa's fight.

For an extended interview with William and Danielle Carney, go to your digital cable box and select iO Extra on Ch. 612.