By Jane Elliott
BBC News health reporter
Ria Hickerton was always active and healthy - a member of her local swimming club.
Ria had been fit and healthy
So when her parents got a call to say that she had collapsed at her part-time job they were shocked.
Before they could get to the library where she worked, Ria had died, just two days before her 17th birthday.
Her parents, Andrea and Alex, then faced a battle to find out why.
A post-mortem gave the cause of death as epilepsy, but Andrea said they were sure that was wrong.
"It took them nine weeks to give us a reason, and when they did they said she had suffered a massive epileptic fit, but we were not happy with this.
"There had never been any sign of epilepsy."
The family were determined to keep probing until they got a more satisfactory answer.
Someone had told Andrea's sister, who used to work for the ambulance service, about Sudden Adult Death Syndrome (SAD).
Could this be the answer?
Andrea said: "Eventually the pathologist said it was more than likely that this was what had happened, but that once she had died there was no way they could prove there was an irregularity in the heart because it had already stopped."
Ria's younger brother and sister were then screened for heart abnormalities and given the all-clear.
"Our local GP was really helpful. Our initial thought was to panic about the other children, so we had them monitored," said Andrea.
Ria's family want to see screening introduced
"We tried to keep things as normal as possible for them, but obviously it will never be completely normal. We do try to be positive."
SAD is now becoming widely recognised as a condition, but Andrea said there needed to be more research into why and how it happened.
She said she would like to see technology advance to the stage where a simple blood test could determine whether children, or young adults, are at risk.
"We want it to be recognised as a problem."
Anne Jolly, chairperson for the Ashley Jolly SAD Trust (SADS UK) said she too hoped a test would eventually be viable.
Anne set the Trust up after her fit and healthy 16-year-old son Ashley died unexpectedly in his sleep.
She said: "I believe it will be possible in the future. At the moment people we know to be at risk or who have had someone in their family die should be checked out.
"In the past this has not always been done."
Andrew Grace, Consultant Cardiologist at Papworth Hospital, in Cambridge, said that SADS was relatively rare, with no more than 300 deaths a year.
He said it generally affected young people from their teens to early thirties.
However, because many of those who died had been previously healthy they had not had electrocardiogram (ECG) to check their heart.
Therefore it was often difficult to pinpoint the cause of death.
"After a sudden death case one could save DNA from that individual for future analysis," said Dr Grace.
"The problem is that we do not know all the genes that may be implicated at the moment and therefore one cannot screen for anything but a proportion of the relevant causes.
"What is more commonly done is to look at the ECGs of siblings and possibly also take blood samples from them for later DNA analysis."
Dr Grace said a national screening programme would not be a good way for doctors to find the small number of cases involved.
Instead, a better way of finding out who was at risk was to look out for warning signs - such as faints or unexpected falls.
Then he said the person should be referred to a specialist for investigation.
"This is not just feeling dizzy when they get up - that can affect anyone," he said.
"But if somebody faints unexpectedly they or if their heart beats very suddenly they should see an expert.
"I don't think they would be at risk of sudden death necessarily, but they should still see an expert."
An embroidered display commemorating Ria's life and aiming to safeguard against SAD has been touring the country.