Kerry and Doron Rosenfeld's world collapsed when their five-year-old son Gavriel was diagnosed with Duchenne muscular dystrophy, a progressive muscle-wasting disease that kills sufferers before their 30s.
But through their despair, the Hendon couple were determined to help find a cure for the condition, which is currently fatal in all cases and affects 300,000 people worldwide. After the diagnosis, they established the Duchenne Research Fund in 2007, which last week raised £1.2 million from a gala dinner in central London. And medical experts say they are on the verge of a treatment breakthrough.
Mrs Rosenfeld recalled that for "the first few years of his life, Gavriel seemed to be doing so well, which is why the shock of him starting to fall hard and regularly was very scary".
They had never heard of the disease, which causes muscles to deteriorate, leading to paralysis and heart and lung failure."But we were soon to learn our baby's life would go in reverse."
Taking up the story, Mr Rosenfeld said: "You just don't believe it and you go into complete shock. You see your son starting out fine. But then he's limping and saying he's tired - and then he's got his first wheelchair.
You think it can't get worse - but it is only the beginning
"Before you know it, he is 14 and you are lifting him from his bed to his chair and pushing him wherever he goes.
"He is completely dependent on you and you think it can't get any worse. Then you suddenly remember this is only the beginning."
He added: "He has been in a wheelchair for two years and we are seeing other signs of the rapid onslaught of his devastating condition on his body with every day that passes.
"But he is what motivates us. We want to find a cure for him and the thousands of other boys like him.
"And it looks as though that is likely. We hope he will be able to maintain his life through drugs in a similar way that people with HIV live with the condition."
Addressing the 740 guests at the London dinner, the head of the charity's scientific advisory board, Dr Ronald Cohn, talked of "a very exciting time. What seemed impossible just a few years ago is now doable because of technological advances."
Effective treatments were on the horizon because of gene therapy research the charity had helped to fund. "We are close to clinical trials."
Gavriel, who attends JFS, featured in an appeal video. "Knowing my parents are going all out makes me really hopeful and trusting," he said. "Occasionally, I get a bit depressed about things that are happening to my body. I get angry and scared and I start crying.
"My brain seems to just explode with fear. It really upsets me.
"But I know in the end they will find something to give me a better quality of life - and other boys around the world. I just feel bad my parents have to deal with this. I don't think it is fair on them and they deserve to have a normal life without these stresses."
Also in the video, one of the Rosenfelds' three other children, Mia-Sara, 10, said: "I don't like watching my brother in the pain he is in and it is hard for me because when I go round to my friends' houses and I see all their brothers running.around. I just really want him to not get worse and hopefully the scientists will find a cure."