THE sisters and parents of a seemingly healthy teenager who died in her sleep are facing medical checks for the adult version of cot death syndrome.

Claire Avery was a lively, happy 18-year-old when she passed away without warning asleep in her boyfriend's arms last August at her home in Derwent Road, Ferryhill, County Durham.

Now the five sisters and half sisters she loved to fuss over and "mother" are waiting for hospital tests to see if they suffer from a rare, inherited heart abnormality which affects one in 10,000 people.

Home office pathologist Dr Mark Egan told an inquest at Bishop Auckland yesterday that Claire was a victim of Sudden Adult Death Syndrome (SADS).

Like other victims, she had no symptoms, and her apparently healthy heart just stopped beating without warning.

Fearing that her family may have an inherited condition affecting the heart's rhythm called Long QT syndrome, doctors have arranged for hospital checks for her father, Steven, her sisters Kelly, 21, and Nicola, 14, her father's daughters, Brianne, four, and Ebonie, one, her mother, Margaret Pybus, and her mother's one-year-old daughter, Nyomi.

Mr Avery, a 39-year-old lathe operator, from Richmond Close, Ferryhill, said: "Claire was fit and healthy but she died. She was a happy loving girl who loved her family and was a mother to all her sisters. She really, really, loved kids."

Claire had taken art and business A-levels at Ferryhill Comprehensive School and had started her first job. Her boyfriend of two years, Kevin Hodgson, is a promising young footballer.

She had enjoyed running at school and the only sign of possible health problems was a couple of fainting fits, which are not uncommon in teenage girls.

A study has discovered that more than 1,000 of the 3,000 unexpected adult deaths each year may be due to SADS.

For information on SADS, contact 01277 230642 or www.sadsuk.org.