A new study by Uppsala University researchers suggests that men with blood cells lacking the Y chromosome are at an increased risk of developing Alzheimer's disease, as well as an increased risk of death from numerous cancers.

The loss of the Y chromosome (LOY) is the most common genetic mutation acquired in a man's lifetime and affects approximately 20 percent of men over the age of 80. In the current study, the team investigated this loss in more than 3,200 men between the ages of 37 and 96.

The results revealed that approximately 17 percent of the men in the study showed LOY in blood cells, and this number increased with age. In addition, those with an existing Alzheimer's disease (AD) diagnosis had a higher degree of LOY, and LOY was connected to a higher likelihood of developing the disease during the follow-up period that took place after the study.

"The idea for this research project came to me when I was writing our first paper on the relationship between LOY and the development of non-blood cancers," said Lars Forsberg of Uppsala University and senior author of the study. "In thinking about the process known as immunosurveillance - the body's ability to fight disease development throughout life - I found that it had been well studied in AD, and hence it occurred to me that LOY might be involved in this disease too."

Forsberg and his team used molecular techniques to reveal the connection between LOY and Alzheimer's disease, as well as its connection to an increased risk of death in men with numerous cancers, although the mechanisms behind these findings are still hazy. The team hopes to continue investigating LOY and its effects in various groups of men with other kinds of diseases and its potential link with early signs of dementia.

Forsberg hopes that in the future, the study's findings will be used to integrate LOY testing in the diagnosis of disease risks in combination with other biomarkers.

"The addition of LOY testing in the general population could give medical practitioners the possibility of using preventive strategies in men at risk," he said. "For example, in cancer, primary tumors are usually not deadly; it is the metastatic process that it normally responsible for deaths. If we could predict which men have an increased risk of cancer, we could watch them closely for the development of disease and also use appropriate preventive treatments.

"In short, the widespread use of LOY testing could radically decrease male mortality rates, and even perhaps eliminate the difference in life expectancy between the sexes," he concluded.

The findings were published May 23 in the American Journal of Human Genetics.