Loss of Y chromosome linked with increased Alzheimer's risk

A pair of elderly couples view the ocean and waves along the beach in La Jolla, California March 8, 2012. (REUTERS/Mike Blake)

Researchers know the loss of the Y chromosome in batches of blood cells is one reason men have shorter lifespans than women, but a recent study suggests this absence also may be a risk factor for Alzheimer’s disease.

In a study published Monday in the journal American Journal of Human Genetics, researchers reported that men with blood samples showing loss of a Y chromosome developed Alzheimer’s disease as often as people born with genetic risk factors for the disease.

“Most genetic research today is focused on inherited gene variants— mutations that are inherited by the offspring— but what we’re looking at are postzygotic mutations that are acquired during life,” said senior study author Lars Forsberg, a researcher in the department of immunology, genetics and pathology at Uppsala University in Sweden, according to Science Daily.

Loss of Y occurs in up to 17 percent of men, Science Daily reported, especially in older men and those who smoke. While it’s been previously linked to a higher risk of developing certain cancers, researchers believe the new findings mean that loss of Y could be a predictive biomarker for Alzheimer’s and other diseases.

The study analyzed blood samples from more than 3,000 men who had participated in three other studies. Those with the highest number of blood cells without a Y chromosome were more likely to be diagnosed with Alzheimer’s disease. Researchers did not say why loss of Y leads to the disease, and said that further study would be needed to prove whether this relationship is causal.

“Having loss of Y is not 100 percent predictive that you will have either cancer or Alzheimer’s,” Forsberg said, according to Science Daily. “But in the future, loss of Y in blood cells can become a new biomarker for disease risk, and perhaps evaluation can make a difference in detecting and treating problems early.”

Forsberg and his team plan to explore how loss of Y affects different types of blood cells, and how it determines risk for specific types of cancers and disease, Science Daily reported.