Thursday 23 March 2017

Life expectancy gap linked to loss of Y chromosome in men

Scientists at Uppsala University in Sweden have found it is possible to test for loss of the Y chromosome
Scientists at Uppsala University in Sweden have found it is possible to test for loss of the Y chromosome

Sarah Knapton in London

A simple blood test to identify if males have lost crucial genetic material as they get older could finally close the gap in life expectancy between men and women, scientists believe.

New research shows that when men lose their Y sex chromosome they are hundreds of times more likely to develop Alzheimer's disease.

Previous research has shown that smoking hugely increases the risk of losing the Y chromosome, suggesting that the missing genetic material may also be linked to cancer.

It is thought that the Y chromosome is crucial for the normal function of the immune system and without it the body struggles to eliminate cancerous cells, and amyloid plaques in the brain which cause Alzheimer's disease.

Now scientists at Uppsala University in Sweden have found it is possible to test for loss of the chromosome, in a breakthrough which could lead to widespread screening which could pick up which men are at risk so that early health interventions could be made.

"The addition of testing in the general population could give medical practitioners the possibility of using preventive strategies in men at risk," said lead author Prof Lars Forsberg.

Disease

"If we could predict which men have an increased risk, we could watch them closely for the development of disease and also use appropriate preventive treatments.

"For example, in cancer, primary tumours are usually not deadly; it is the metastatic process that is normally responsible for deaths.

"If we could predict which men have an increased risk, we could watch them closely for the development of disease and also use appropriate preventive treatments. In short, the widespread use of testing could radically decrease male mortality rates, and even perhaps eliminate the difference in life expectancy between the sexes."

In humans each cell contains 23 pairs of chromosomes, 22 of which look the same and are called autosomes, and a 23rd pair which are the sex chromosomes. Women have two copies of the X chromosome, while males have one X and one Y chromosome.

It has been suggested that women live longer because they do not have a Y chromosome to lose. The average man in Britain lives until 79.5 while women can expect to live to 83.2.

The loss of the Y chromosome - known as LOY - is known to affect up to 20 per cent of men who are aged over 80, and is the most common genetic mutation acquired during a man's lifetime. (© Daily Telegraph, London)

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