A young boy penned a moving letter to celebrate the fact his mother had received a working kidney in time for Christmas.
Deirdre Cole says her life has been utterly changed as a result of her brother donating one of his kidneys to her.
She is asking families to use the Christmas holidays to talk about organ donation.
The family celebrated her son Andy turning eight on Christmas eve and the "Super Kidney" his mum now has, thanks to his uncle, inspired him to write a moving letter.
"Once upon a time there was an ordinary man called David and his sister Dee and her kidneys stopped working, oh-no: trouble at the double.
"Here comes Super Kidney to save Dee's day. This is how an ordinary man became a superhero," he wrote
Ms Cole (42) added: "I believe my brother David's selfless act was life-altering because the only other certainty I had was that I would get sicker.
"I can make plans now. This Christmas is incredible and compared to last year, there is huge comfort in knowing I am not sick any more."
Ms Cole said very high blood pressure led to her finding out she had kidney disease when she was just 20.
When she was pregnant with Andy, she was extremely ill because of her condition.
In December 2014, she was told she was six months from needing dialysis. Ms Cole moved back to her hometown of Cork and was under the care of the renal team in Cork University Hospital.
She made efforts to follow a strict diet, along with reducing work to three days a week, and was able to delay dialysis.
Ms Cole needed either a member of her family to be a perfect match. She and partner Brian McLoughlin (45) were planning to go to the UK to find a paired donation.
"David and his wife Aran called me and said he was in the final process of being tested to see if he was a match," she said. "I just burst into tears."
On November 26 - one month ago today - they had the operation in Beaumont Hospital in Dublin. "I am able to plan for the future now," she said. "For the last five years I have not been able to do that."
They are supporting the Irish Kidney Association's campaign to discuss organ donation this Christmas.
For organ donor cards Freetext DONOR to 50050 or visit website www.ika.ie/card.
Wishes to be an organ donor can be included on the new driving licence (Code 115) or a free "digital organ donor card" app can be downloaded on to a mobile phone.