Parents Tony and Mary Heffernan's dream came true, of their young two-year old son Liam playing at home with his toys like any other energetic toddler. This is a huge step forward for the Heffernan family, as only two months ago Liam could hardly talk or walk.
"Before the treatment, Liam had a vocabulary of about 20 words. Now he has about 60 or 70 words. And you just heard him saying 'juice'. It is unbelievable," Tony tells the Irish Independent. "He is now walking around like any other two-year-old and we're absolutely thrilled with how he is doing so far."
Liam Heffernan from Castledrum, Keel in Co Kerry, suffers from a rare neurological disorder called Battens Disease. The young boy is now the youngest child to ever undergo a gene transfer procedure, which took place earlier this month in New York.
After a 24-hour scan to measure electrical activity in his brain, the doctors at Weill Cornell University Hospital drilled six holes into the toddler's skull as part of the surgical procedure.
The family from County Kerry in the south-west of Ireland, on their way home from the United States, visited the grave of their daughter Saoirse who died in January of this year from the same disorder. Five year old Saoirse was too weak to undergo the revolutionary treatment her younger brother Liam has successfully undergone.
They arrived home to a welcoming party of their parents, relatives, neighbours and friends, after five nerve-wrecking weeks in New York.
Usually after this treatment there is a one-month check-up period, however, such is the remarkable recovery and progress witnessed in Liam recently that the doctors have fixed his next appointment for November.
"They have given us a check-up and treatment schedule which runs up until 2026, a 15-year plan. So we are taking that as a very good sign," Tony tells the Independent.
Tony and Mary still have to undertake a detailed daily checklist for any sign that Liam's gene-therapy treatment may be running into problems. "We have to check his temperature, and his skin for any signs of bruising, marks or rashes. The results are then faxed over to New York," adds the Independent.