A teenager's sudden death from an undiagnosed heart complaint has made her family determined to ensure others do not suffer their loss.

Kasia Ber, 17, died at her home in Brier Avenue, Horden, East Durham, on the morning of December 28, last year. 

It was only discovered after she died that she had been suffering from a genetic heart condition known as Long QT syndrome. 

Her aunt died from a sudden arrhythmia and her mother, Diane, takes beta blockers to treat Long QT syndrome. 

Since Kasia's death, her two cousins have been diagnosed with the condition. 

Mrs Ber said: "We cannot bear the thought of something like this happening to our daughter and nothing coming of it. 

"We want to raise awareness so that people will not have to suffer in the same way that we have suffered. 

" We feel really bitter, angry and frustrated that this is still happening." 

Kasia's father, John, said they had received a lot of support and help from the charity Cardiac Risk in the Young (Cry), which was formed in 1995 to raise awareness of sudden death syndrome in young people. 

Levon Morland, from West Rainton, County Durham, collapsed and died as the result of a rare heart syndrome four years ago. 

Since then, his family and friends have raised more than £100,000 for the charity. 

Last night, his father, Jeff, said: "Our first thoughts are with the family who are left behind with all the suffering. 

"There is a lot more awareness now than ever before, but the problem we have got is raising awareness throughout the medical profession." 

Dari Taylor, MP for Stockton South, pushed through a Private Member's Bill in the Commons two years ago calling for CPs to be given directives on how to deal with such cases.  Along with Durham North MP Kevan Jones, she has continued to campaign for the screening of youngsters. 

Cry founder and chief executive Alison Cox said: "This death is another appalling example of the kind of tragedy we have to regularly confront at Cry.

"Kasia's death is absolutely inexcusable, as it was treatable. 

"It takes enormous courage for Kasia's family to want to help others and raise awareness of Cry and young sudden cardiac death in the face of the terrible and absolutely unnecessary loss of their child." 

The Bers have set up a memorial fund as a tribute to Kasia, with money raised through events going to Cry and towards buying equipment for their community. 

A Halloween disco at Horden Rugby Club raised more than £700 for the fund, and some of Kasia's friends had their legs and chests waxed, raising more than £600.