Why do men live relatively shorter lives than women? This question might be partly answered by new findings recently published in the American Journal of Human Genetics: the loss of Y chromosome in blood cells of some men might be linked with Alzheimer’s disease.
To test their hypothesis of whether loss of Y chromosome in blood cells and Alzheimer’s are linked, the researchers analysed data from 3,000 men. Their results show that those having the greater number of blood cells missing a Y chromosome were also more likely to develop the disease.
The researchers found that the frequency of Alzheimer’s in men with blood samples displaying a loss in chromosome Y was similar to that of people bearing genes that make them susceptible to the disease. They discovered this potential link when they examined genetic variations that build up with time: these are known as postzygotic mutations, defined as those acquired later in life, as opposed to inherited gene variants that are innate (as indicated by its name).
They were able to identify one postzygotic mutation in the cells of males that is characterised by the loss of the Y chromosome in blood cells. The loss of this chromosome in particular is generally found in older men, and in smokers. It has been described as a risk factor for cancer. The new study, thus, shows that it might also be indicative of other negative health outcomes like Alzheimer’s. The team explain that loss of Y can be a predictive biomarker for these conditons; they were, however, unable to explain the link.
Since the Y chromosome is specific to men, and that its loss pertains to the risk of the disease, this finding could explain why men generally tend to live shorter lives than women.
Author Lars Forsberg explains that this link is not an absolute fact, that is, the loss of Y does not mean that the person will surely have cancer or Alzheimer’s; some men in the study lost the Y in their blood cells without showing any symptoms in their later years. But, Forsberg does add that loss of Y might become a new biomarker to indicate risks of diseases.