Swiss researchers reported that a variant form of a gene that helps the brain break down cholesterol may play a role in some cases of Alzheimer's disease.

The variation of gene, called CYP46, may hamper production of an enzyme that aids the brain in processing excess cholesterol, resulting in a buildup of cholesterol and the beta-amyloid plaques found in the brains of Alzheimer patients.

The Swiss study found that people with this gene variant are at twice the risk of developing late-onset Alzheimer's.

The gene is the second found by researchers linked to Alzheimer's. A defective form of APOE4, which also plays a role in processing cholesterol, previously has been shown to increase Alzheimer's risk.

People with mutated forms of both the CYP46 and APOE-4 genes are almost 10 times more likely to develop Alzheimer's as those without either mutation, the researchers reported in the journal Archives of Neurology.

"These observations underscore a possible relationship between cholesterol and brain amyloid formation," the researchers concluded.

Other sources: Archives of Neurology