Johanna Hughes, 26, might not be alive today if it wasn't for her brother Joseph.
The 24-year-old braved the surgeon's knife to donate his kidney after both her mother and father tried to save her life.
Johanna's body rejected her mum Suzanne's kidney after only one night.
Then her father Joseph, 53, stepped in but after almost six months of positive tests, the family were to suffer more heartache when the last one came back negative.
By this time Johanna had already had two transplants, at the age of seven and 18, and she was told her body would reject 98% of kidneys.
Johanna had also spent so many years on dialysis that she was running out of access points for the needle. Seriously ill, she was put on the "critical" list.
Her brother was her last hope. Two days after her 25th birthday on July 4, last year, the first test showed he was the perfect match.
Doctors had to rush through the other tests because Johanna was so ill.
Three days after Christmas, Johanna was given her brother's kidney and her body did not produce a single antibody.
She said: "I can't even begin to describe how much I love my brother. We have this really amazing bond.
"He knew how much I wanted my life back. It's completely life-changing."
Joseph said: "The first thing I did when I woke up was ask how she was. Me and Johanna have always been best friends.
"It was like seeing your best friend get better. Seeing her get on with her life, that's what makes me happy."
Johanna, who lives in Paisley, was diagnosed with glomerular nephritis as the age of three, a type of renal disease that usually affects both kidneys.
Suzanne, 50, an NHS worker, who lives in Cumbernauld, said: "It was a bit of a shock. There is no history of kidney disease in the family."
Johanna had her first kidney transplant when she was seven at Yorkhill Hospital, which allowed her to have a normal childhood and teenage life.
However, by the time she was 18 the kidney began to fail and it was clear she would need another transplant.
It was then, that Suzanne decided to get tested to see if she could be a match for her daughter. Two years, later the operation went ahead.
However, Johanna's body rejected the kidney and surgeons were forced to remove it after only one night.
"It was heart breaking" says Suzanne.
"You are doing this to try to save your daughter's life, so finding it out it hadn't worked was devastating. There is a 95% success rate with family.
"They couldn't explain why it happened. She had to go back on dialysis, for the next five years."
Between times her father Joseph put himself forward as a donor. But after almost six months of positive tests, the last one came back negative, ruling out a transplant.
Johanna said: "When my mum's kidney failed I felt as if my world had ended. It was getting to the stage where I thought, if this doesn't work out then I just can't carry on with dialysis.
"I was in and out of hospital every other day for procedures to try to improve my veins. I was getting to the end stage. I had to get a transplant.
"I was depressed, I had no life. I thought, this is not going to happen for me.
"I knew I didn't want to go back on dialysis. The psychological effects of being on dialysis are so different for young people. It's not really highlighted."
Doctors wanted to wait until Joseph was older before he was tested, so last year, in March, when he was 22, he had his first test, which showed he was a perfect match.
He said: "It was so hard watching her get sicker and knowing how her illness was going to progress. I was her last chance."
Johanna and her brother, who is studying TV production, were admitted to the Western Infirmary on December 28, last year, for the transplant.
Suzanne said: "They took Joseph in first to remove his kidney and then got Johanna down. It was very difficult having to say goodbye to both of my children. It was the one option for Johanna and obviously he had made the decision. He loves her and wanted to save her life."
The operation was a complete success and Johanna's body did not make a single antibody to her brother's kidney.
She said: "When I saw him the next day I just burst into tears. It's quite emotional even talking about it. We have this really amazing bond.
"I live a normal life now, a functioning life."
Johanna, who is now training to be a nurse, is a firm believer that Scotland should follow Wales and switch to an opt-out system to increase the pool of donors.
She said: "I truly believe the opt-out system is the best system. If you expect to get an organ you should be prepared to donate one."
Both Suzanne and Johanna are taking part in the seven-mile Bridges Walk on Sunday to raise money for Kidney Research UK.
The event starts at 10am from the Riverside Museum and entrants can still register on the day before 10am.
For more info, visit www.support.kidneyresearchuk.org and follow the links.