Loss of Y chromosome may increase Alzheimer's risk in men

Men with blood cells that do not carry the Y chromosome are at higher risk of being diagnosed with Alzheimer's disease, says a study.

The Y chromosome is one of the two sex chromosomes in humans - the other is the X chromosome. Women do not carry a Y chromosome.

The loss of the Y chromosome (LOY) is known to affect up to 20 percent of men who are aged over 80, and is the most common genetic mutation acquired during a man's lifetime.

The international team of researchers investigated loss of the Y chromosome in over 3,200 men with an average age of 73, and an age range of 37-96.

The researchers found that those with an existing diagnosis of Alzheimer's disease (AD) had a higher degree of loss of the Y chromosome, and that it was also a marker for the likelihood of developing the disease during the follow-up period.

The findings, published in American Journal of Human Genetics, could lead to a simple test to identify those at risk of developing Alzheimer's disease.

"The addition of LOY (loss of the Y chromosome) testing in the general population could give medical practitioners the possibility of using preventive strategies in men at risk," said one of the researchers Lars Forsberg from Uppsala University in Sweden.

Using standard molecular techniques, the identification of loss of the Y chromosome in blood is easy to determine when it occurs in 10 percent or more of blood cells with a nucleus containing DNA.

As well as being relatively common in older men, it also occurs less frequently in those who are younger.

Since women do not carry a Y chromosome, and men have, on average, shorter lives, it is possible that loss of the Y chromosome may be related to the earlier death of men.

The researchers noted that Alzheimer's risk due to loss of the Y chromosome in blood cells is in addition to an increased risk of death from other causes, including many cancers.

"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," Lars Forsberg pointed out.

--IANS

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