A Long Island mother is determined to raise awareness about a rare genetic disease after her daughter was misdiagnosed.

At first, Leah Lupo says doctors didn't know what her daughter, Antonia, was ailing from.

"I had one doctor saying she could potentially have Down syndrome and another said I think that she's fine. Go on with life," Lupo told News 12 Long Island. 

Eventually, Antonia was diagnosed with the genetic condition known as Feingold syndrome. Doctors say the condition can be hereditary, but isn't always. It occurs when there's a partial deletion of chromosome 2. Patients can suffer from growth and developmental delays, as well as problems with their heart, stomach and teeth.

In recent years, only 79 cases were reported worldwide. 

"When you're a parent…it's the scariest thing to hear a doctor say, 'We've never treated a patient with this before,'" says Lupo. 

The mother says her daughter is doing well with the help of doctors at Cohen Children's Hospital.

Doctors say there are no current research studies on Feingold syndrome. Research by Dr. Murray Feingold, for whom the condition is named, stopped after he passed away in 2015.