A two-year-old Irish boy is set to become the world's youngest child to undergo pioneering brain surgery.
Liam Heffernan, who suffers from Battens disease, leaves from Dublin Airport today to participate in a medical treatment trial in the United States.
The surgery, which involves six holes being drilled into Liam's skull, is scheduled to take place on 3 May - exactly 15 weeks after his only sibling died from the same rare and fatal disorder of the nervous system.
Five-year-old Saoirse died on 18 January.
His father said the treatment in New York is the couple's only chance of saving their child.
'There's no guarantees with this and we know that,' said Mr Heffernan.
'But this is the second time they've got kids on this trial and it's proved positive so far so we just hope Liam has the same result. It means everything to us.'
Less than 1,000 children worldwide have Late Infantile Battens Disease, with just a handful of sufferers in Ireland.
It is an inherited disorder of the nervous system which causes mental impairment, seizures and progressive loss of sight and motor skills.
Early symptoms include vision problems or seizures, delayed speech, slow learning, clumsiness or stumbling.
The family, from Castledrum in Keel, Co Kerry, will travel to the prestigious Weill Cornell University Hospital for the surgery, which involves gene transfer treatment to 12 locations in Liam's brain.
Since the medical trial began in August 2010 only four children, all of whom are American, have received the gene transfer.
The trial co-ordinators recently got permission from the US federal authorities to treat Liam following their application to reduce the participation age below the three-year-old minimum age requirement.
Mr Heffernan said while Liam has never been healthier, he is beginning to lose his balance and is on a liquid diet as he cannot swallow.
'He is a typical two-year-old boy,' said his father.
'Full of life and full of interaction, a sweetheart one minute and a gangster the next.'
Liam will remain in the US for one month after surgery and is expected to return to Ireland just in time for World Battens Day, on 4 June.
Balloons will be released on the day to mark what would have been Saoirse's sixth birthday and bands and artists will perform at The Kerry Way in Killarney in aid of Bee for Battens.
The charity is raising funds to pay for other Irish children to undergo medical treatment trials, fund research and support sufferers and their families.
