BioNews reporting from the British Society for Human Genetics (BSHG) annual conference in Warwick:

Clinicians should be cautious about offering genetic testing to patients at risk from Huntington's disease to enable them to participate in clinical trials, Dr Sheila Simpson, a Clinical Geneticist at NHS Grampian Hospital, said in a talk at the annual conference of the British Society of Human Genetics at Warwick University.

Dr Simpson says: 'Research into Huntington's disease has progressed significantly in the last decade and there are now a number of very promising new treatments which could enter clinical trials within the next few years. Many families see this as a potential lifeline. This could prompt those at risk of Huntington's disease to undergo testing without considering the full implications of the test.'

Huntington's disease is an inherited neurodegenerative disease leading to personality changes, involuntary movements, cognitive decline and eventually death up to 20 years after diagnosis. Those with an affected parent have a 50 per cent chance of having inherited the gene and developing the condition themselves. Symptoms do not usually become apparent until middle age, which is often after the person has had children of their own.

Some of the first clinical trials of new treatments that could slow down progression of Huntington's may start soon, and many others - shown to be effective in animal models - are being explored for testing in humans. Research shows that at present only 15-20 per cent of patients with an affected parent opt to be tested to find out whether they have inherited the Huntington's gene. This may change, as new hopes for treatment emerge.

Dr Simpson says: 'This test is an incredibly powerful tool which effectively allows patients to find out their future. Both favourable and unfavourable genetic test results can have serious implications for the whole family, and surprisingly it's often those who receive favourable results who find it hardest to cope. Depression, marital breakup and sometimes suicide can occur following test results and I believe it is essential that patients of all ages continue to receive adequate preparation for testing which is appropriate for their individual circumstances. This will ensure that those deciding to take a test are doing so for the right reasons.'