A gene allele that increases the risk of Alzheimer’s disease starts to damage the brain 50 years before symptoms of the disease appear, a new study suggests. An allele is one of two or more forms of a gene. In 2009, scientists concluded that the clusterin (CLU) gene boosts the chances of Alzheimer’s disease by 16 percent, but it wasn’t clear how it increased risk. This new study concluded that the C-allele of the CLU gene impairs development of myelin, the protective covering around the axons of neurons in the brain. This impairs brain wiring and can make a person more vulnerable to the onset of Alzheimer’s later in life.
