By Melissa Jackson
BBC News Online health staff
It is hard to imagine how a teenager who is healthy and lively one day can suddenly drop dead the next for no apparent reason.
Alison died on her first day at college
Such is the tragedy of sudden cardiac death in the young.
It is a cruel, indiscriminate condition that claims the lives of eight young people every week in the UK.
Most people do not even know it exists until it strikes someone in their own family.
But a campaign has been launched to raise awareness of the condition and ensure better facilities for diagnosis and treatment.
It has been organised by Cardiac Risk in the Young (Cry) - the national charity dedicated to helping the families of those who have lost someone under the age of 35 to sudden cardiac death.
One of the people spearheading the campaign, along with hundreds of other parents who have experienced the trauma of losing a son or daughter, is Eve Linforth.
For her 11 September holds a very personal significance.
It was on this date last year that her daughter Alison, an attractive 16-year-old, set off for her first day at college as an A-level student.
What should have been the start of an exciting new chapter, turned out to be the last day of her young life.
Mrs Linforth, from Birmingham, received a telephone call from the college that morning to say that her daughter had collapsed in the classroom and attempts to resuscitate her had failed.
She said her daughter had always enjoyed good health and had shown no signs of any heart condition, although she had once complained of small chest pains a couple of months before her death.
These were attributed to indigestion, which was treated successfully at the time with a couple of indigestion tablets.
On the first day of term, Alison was a bit nervous, like all new students, said her mother.
Mrs Linforth said: "She had been celebrating her sister's 20th birthday the night before.
"We'd had a family party.
"She went to college with her friend, who later told us that she had complained about having a very dry throat on the way there, but that could have been nerves.
"She went off to find her first class in the art room.
"She got to her class and sat down and they called out names and the next thing her friend said was that she thought Alison had fallen asleep.
"But she had fallen onto her friend's shoulder and died.
"The college first-aiders tried resuscitation and then paramedics came and tried the same, but there was nothing they could do."
The coroner could not establish a specific cause of death and recorded a verdict of death by natural causes.
Alison's death was not the first inexplicable fatality in the Linforth household.
They lost another daughter, Amanda, to cot-death at eight weeks old. She would now be 18.
And another daughter, who would now be 15, was stillborn.
Alison's death made Mrs Linforth question whether there is a genetic heart condition in the family, which caused all three girls' deaths.
To find out, she and Alison's elder sister Gemma, 20, are having their DNA checked, and both have undergone heart screening.
Mrs Linforth is now backing Cry's campaign for better cardiac screening for young people who go to the doctor with inexplicable chest pains or for the siblings of a child who has died from a sudden cardiac death.
Mrs Linforth said: "If screening had been around when Alison was a baby, they might have picked up that she had some sort of problem.
"We still feel cheated because we haven't had a cause of death and didn't with our other two daughters.
"I still blame myself now along the lines of 'if only I'd taken her to the doctors when she had chest pains'.
"Alison's death will always be with us, but if we can help someone else, it means it hasn't been in vain."
Aside from the inexplicable fatalities, there are several known causes of sudden cardiac death.
Among them are hypertrophic cardiomyopathy (HCM) - a hereditary condition in which there is excessive thickening in the heart muscle, myocarditis, which leads to inflammation of the heart muscle and coronary artery disease.
Cry has been successful in lobbying parliament to set up an all-party parliamentary consultation body which will advise the Department of Health on future policy.
Its findings will be published next March and it will lead to a new chapter being added to the National Service Framework (NSF) on coronary heart disease, setting out the standards and models of care for such conditions.
Cry's chief executive Alison Cox said things are gradually changing for the better within the medical profession.
She said: "Younger doctors are being trained now to recognise the symptoms that could indicate a heart problem.
"I think younger doctors have an advantage over older ones.
"Here at Cry, we arm parents with information written by experts, which empowers them so that they can go to their GP and ask to have their son or daughter screened."