Saoirse Heffernan, of Castlemain, County Kerry, has arrived in New York to take part in a ground breaking medical trial at Cornell University.

The five-year-old suffers from a rare neurodegenerative disorder neuronal ceroid lipofuscinosis, known as Late Infantile Batten's Disease.

She was diagnosed last September along with her 22-month-old brother, Liam. There is no known cure for the disease and without treatment it is thought that she will not live to see her 11th year.

This disorder affects less than one in a million children including Saoirse and Liam. The disease causes brain cells to die, leading to blindness, a progressive loss of motor skills and brain function and ultimately death. Saoirse has already lost 70 percent of vision.

Saoirse and Liam take a cocktail of drugs to prevent them having some of the 200 seizures they suffer each day.

The disease effectively causes the brain to poison itself due to the lack of a crucial enzyme that clears away fats and proteins in brain cells.

Tony and Mary Heffernan the children’s parents are feeling hopeful now that they are involved in the Cornell University research.

Over the coming weeks Saoirse will undergo a series of tests at the Weill Medical School stem cell research program to make sure she is a suitable candidate for the invasive procedure.

The surgery will involved drilling eight holes into the little girl’s head and injecting a gene which carries the missing enzyme. There is no guarantee that it will work.

"If we don't go on the trials we're told they won't live beyond the age of 10," said Mr Heffernan.

"But they're very confident they'll be able to arrest it. It's hard but we have to try."

If Saoirse is given the all clear for the surgery she will return to New York to undergo surgery over the next 18 months. All going well her little brother Liam will also have access to this surgery.

Mr Heffernan has abandoned his job, as a ship’s captain, to care for his children. He has also set up a charity, Bee for Battens to raise awareness about the disease and funding toward his children’s treatment.

The total cost of enrolling both children in the research program will exceed $980,000.

To learn more visit www.beeforbattens.org.