May 24, 2016

Greater Risk of Alzheimer's in Men Linked to Loss of Y Chromosome in Blood Cells

Men with blood cells that do not carry the Y chromosome are at greater risk of being diagnosed with Alzheimer’s disease.


By Alzheimer's Reading Room

Men with blood samples showing loss of the Y chromosome developed Alzheimer's as often as people born with genes that put them at the most risk for the disease.
Men showing loss of the Y chromosomes in blood samples developed Alzheimer's as often as people born with genes that put them at the most risk for the disease.

Previous research by the same group has shown that smoking greatly increases the risk of acquiring loss of the Y chromosome (LOY) by as much as 400%.


Subscribe to the Alzheimer's Reading Room
Email:
  • Men with blood cells that do not carry the Y chromosome are at greater risk of being diagnosed with Alzheimer’s disease (AD), and this is in addition to an increased risk of death from other causes, including many cancers.
  • The loss of the Y chromosome, or LOY, is known to affect up to 20% of men who are aged over 80, and is the most common genetic mutation acquired during a man’s lifetime.
The study investigated LOY in over 3200 men with an average age of 73, and an age range of 37-96. Around 17% of them showed LOY in blood cells, and this increased with age. The researchers found that those with an existing diagnosis of AD had a higher degree of LOY, and that LOY was also a marker for the likelihood of developing the disease during the follow-up period.


Using standard molecular techniques, the identification of LOY in blood is easy to determine when it occurs in 10% 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 LOY may be related to the earlier death of men.

Researchers say the mechanisms and causes for their findings are still not properly understood. They are currently investigating the functional effects of LOY, and looking at its role in different groups of men and in other diseases, in order to understand better which types of cancer are associated with LOY, as well as whether there is a link with early signs of dementia, for example mild cognitive impairment.
  • Previous research by the same group has shown that smoking greatly increases the risk of acquiring LOY, by as much as 400%.
Smoking appears to have a transient effect, and is also dose-dependent, so quitting could reverse the effect. This could be important to emphasize in smoking-cessation programs, the researchers say.

Search the Alzheimer's Reading Room for Answers to your Questions about Alzheimer's and dementia

More difficult to tackle is the question of diagnosis and treatment of serious conditions such as AD and cancer. The development of diagnostic tools for their earlier detection could lead to strategies aimed at preventing their development before symptoms occur.

Topic - Memory Tests

In the future it might be possible to use an LOY test to identify men at risk and then carry out oncological or neurological evaluations to try to detect early, mild, symptoms of disease. LOY might also become an important diagnostic tool in combination with other biomarkers that may be used to predict risks for various diseases.
“The addition of LOY testing in the general population could give medical practitioners the possibility of using preventive strategies in men at risk. 
For example, in cancer, primary tumours 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.” - Professors Lars Forsberg, the Department of Immunology, Genetics and Pathology at Uppsala University

Related

Test Your Memory for Dementia in 15 Minutes (SAGE)

The Mini-Cog Test for Alzheimer's and Dementia

Does Anesthesia Cause Memory Loss or Dementia in the Elderly?

The Alzheimer's Reading Room operates for the benefit of society.

In the Alzheimer's Reading Room, we tackle real world problems and offer advice and solutions on issues like: repetitive questioning, challenging behavior, how to understand Alzheimer's disease, how to cope with the disease, and how to communicate effectively with a person living with dementia.

The Alzheimer's Reading Room contains more than 5,000 articles and has been published daily since July, 2009.

You are reading original content the Alzheimer's Reading Room

Abstract no: C23.1: Mosaic loss of chromosome Y (LOY) in peripheral blood is associated with age, smoking, shorter survival and increased risk of cancer and Alzheimer’s disease

Source: The annual conference of the European Society of Human Genetics, the paper is published in the American Journal of Human Genetics. https://www.eshg.org/835.0.html