Alzheimer's disease currently affects an estimated 14 million people world wide. As the world population and their longevity increase, it is predicted that this figure will continue to rise rapidly. Cognisant of this “time bomb”, scientists across the globe are endeavouring to elucidate the pathogenic mechanisms of the disorder with urgency. Within the past decade, major advances have been made in identifying the genetic causes that result in the abnormal accumulation of beta amyloid, the major component of senile plaques which form one of the neuropathological hallmarks of the disorder.

Dr Tanzi is the Director of the Massachusetts General Hospital's (MGH) Genetics and Aging Unit. With the help of scientific journalist …