A County Durham mother has called for more research into a rare heart condition which could see her son die from someone shouting "boo" at him.
Sudden shocks could kill Bradley, his mother says
Bradley Young, from Newton Aycliffe, must avoid sudden shocks because he has Long QT syndrome, which severely affects blood flow from the heart.
Now the three-year-old avoids anything which could bring on a sudden shock, including bouncy castles and balloons.
His mother Glynis has called for more studies into the genetic condition.
Most people with Long QT Syndrome never know they have it until it is too late, and it has been linked with the deaths of young footballers and some cot deaths.
Bradley was diagnosed when he underwent treatment for asthma and tests showed he had a hole in the heart.
During the operation on his heart, surgeons discovered he was suffering from Long QT syndrome.
His 38-year-old mother said: "We were very lucky that they discovered it when he went in for heart surgery.
"The doctors said with these children, they look normal and healthy and you do not know they are bad until something happens. It is very rare to find it before."
The mother-of-five said beta blocker drugs kept her son stable, but the family took care not to test them too much.
Bradley is not allowed to go on funfair rides, and his friends and family take care not to make loud noises, such as popping a balloon or shouting "boo", when he is around.
Mrs Young added: "It may be a bit extreme, but we don't want to test the treatment too much, and push it too far."
She also urged people to get better awareness of resuscitation techniques for youngsters, which differ from those for adults.