London, Sep 7 - The largest study so far on Alzheimer's disease has helped British and French scientists isolate three new genes associated with it.

They are the first new genes found to be associated with the common form of Alzheimer's disease since 1993. The study involved 16,000 individuals.

The Alzheimer's Research Trust spoke of 'a leap forward for dementia research'. Medical Research Council (MRC)'s Leszek Borysiewicz described it as 'a huge step towards achieving an earlier diagnosis of Alzheimer's'.

Previously only one gene, APOE4, had been associated with Alzheimer's disease. This study revealed two more genes, CLU and PICALM, related to the disease.