Cholesterol control gene could provide dementia protection

American scientists have found that a genetic variation could be associated with slower memory decline and a lower risk of Alzheimer's disease and dementia. The preliminary findings shed light on processes in the brain that could contribute to memory loss and dementia. The work was published in the Journal of the American Medical Association last week.

The study involved 523 participants who took psychological and cognitive tests over four years. During the study 40 people developed dementia. The researchers found that a specific variant, or allele, of the cholesteryl ester transfer protein (CETP) gene was associated with a lower risk of developing Alzheimer's. People with the variant also declined more slowly in the cognitive tests than those without.

Dr Amy Sanders, who led the study at the Einstein College of Medicine, New York, said: 'We found that people with two copies of the longevity variant of CETP had slower memory decline and a lower risk for developing dementia and Alzheimer's disease. More specifically, those participants who carried two copies of the favourable CETP variant had a 70 per cent reduction in their risk for developing Alzheimer's disease compared with participants who carried no copies of this gene variant'.

The CETP gene was previously found to be associated with longevity, and these new findings suggest that it could have a role to play in cognitive function. CETP is involved in the control of the size of cholesterol particles in the body. Other studies have suggested that cholesterol processing could be involved in Alzheimer's, although the exact causes of the disease are unknown.

Most cases of Alzheimer's are not directly inherited from one generation to the next and it is likely that many genes, together with lifestyle factors and life events, cause Alzheimer's. 700,000 people in the UK have dementia, with about two thirds of those cases caused by Alzheimer's disease. Within a generation, as the population ages, it is estimated that there will be 1.4 million people living with dementia. With no cure or effective treatments at the moment, it is hoped that more research like this into the genetics of the disease will help researchers understand its causes, and lead the way to developing new treatments.