The family album brims with pictures of a bouncing baby whose beaming smile would stay with him into adulthood and who by his mother's admission 'grew into his ears'.

But today the only pictures being added are by his friends on the gonetoosoon website - the shocking suddenness of his death still as baffling today as it was in June. 

For Simon Cullum's mother Marilyn Cullum, the deeply felt messages posted on the site bring some comfort while a question mark hangs over her own diagnosis with possibly the same potentially fatal heart defect. 

Car-mad Simon, who lived with his family in Lowestoft Road, Gorleston, was 29 when on a day which was otherwise unremarkable his heart stopped. 

The clean-living warehouseman who said no to drink, drugs and cigarettes, had chatted with his mother about what was for tea and then gone to his bedroom to play computer games. 

Wondering why he hadn't taken the car to keep an appointment his mother went upstairs and found him slumped on the floor. 

She praised the heroic efforts of paramedics but she knew Simon was gone.  For her husband John and Simon's brother Robert, 25, the death has been equally hard to fathom. 

Simon is among at least eight apparently fit and healthy young people to die every week of undiagnosed heart conditions, according the CRY charity - Cardiac Risk in the Young - which is supporting Mrs Cullum with advice and counselling. 

Determined that something good should come of the tragedy Mrs Cullum is adding her voice to the charity's plea for a national screening programme. 

Although no heart defect was found in Simon many of the test that uncover problems can only be carried out on live hearts.  His death certificate records Sudden Adult Death Syndrome (SADS) as the cause of death. 

Mrs Cullum said that routine screening of young people using the quick and  non-invasive ECG test could save lives and takes only two to three minutes.  Although defects are not always picked up and some people need re-testing Mrs Cullum said even if one life were saved it would be worth it. 

The charity, whose patrons include Little Britain star David Walliams and former England cricket captain Ian Botham, paid for extra tests to be carried out on Simon's heart - the results of which could have helped other families, but meant he had to be buried without it. 

Simon was well-known within the car cruising community, earning the nickname The Daddy.  A pin board in his bedroom features a gallery of cars he had owned, his favourite being a gold Orion known as The Onion.  His hobby and social circle was focused o his cars, showing off his latest modifications to mats along Great Yarmouth seafront, where he was a regular cruiser. 

Simon's death meant a round of tests for the extended family, with only Mrs Cullum showing inconclusive diagnosis of Long QT - one of the most common causes of unexpected death in the under 35's.   

"It makes us aware that life is short and uncertain.  There are people of our age dying but you do not expect it in one so young.  Life is too short to bear grudges.  It makes you think that today could be your last," she said. 

To raise funds for and awareness of CRY a coffee morning with stalls, refreshments and raffle is being held in Simon's memory at St Peter's Roman Catholic Church in Lowestoft Road on Saturday 26 from 10.30am.  Entry is 50p including tea and a biscuit.