Some men lose their Y chromosome with age: (10X increase in Alzheimer's, etc )

Men lose their Y chromosome as they age — and it’s no longer harmless - Feb 2026

Snips

... evidence has mounted over the past few years) that when people who have a Y chromosome lose it, the loss is associated with serious diseases throughout the body, contributing to a shorter lifespan.
The increase with age is clear: 40 per cent of 60-year-old men show loss of Y, but 57 per cent of 90-year-olds. Environmental factors such as smoking and exposure to carcinogens also play a role.
The human Y is an odd little chromosome, bearing only 51 protein-coding genes
In mammals, the Y has been degrading for 150 million years and has already been lost and replaced in some rodents.
Loss of Y frequency in kidney cells is associated with kidney disease, COVID, Heart Attacks, Alzheimer's (10X increase), Parkenson's
Researchers transplanted Y-deficient blood cells into irradiated mice, which then displayed increased frequencies of age-related pathologies including poorer cardiac function and subsequent heart failure.
The DNA of the human Y was only fully sequenced a couple of years ago – so in time we may track down how particular genes cause these negative health effects.

Loss of the Y Chromosome: A Review of Molecular Mechanisms, Age Inference, and Implications for Men’s Health - 2024

Int. J. Mol. Sci. 2024, 25(8), 4230; https://doi.org/10.3390/ijms25084230 Mexico

Until a few years ago, it was believed that the gradual mosaic loss of the Y chromosome (mLOY) was a normal age-related process. However, it is now known that mLOY is associated with a wide variety of pathologies in men, such as

cardiovascular diseases,
neurodegenerative disorders, and
many types of cancer.

Nevertheless, the mechanisms that generate mLOY in men have not been studied so far. This task is of great importance because it will allow focusing on possible methods of prophylaxis or therapy for diseases associated with mLOY. On the other hand, it would allow better understanding of mLOY as a possible marker for inferring the age of male samples in cases of human identification. Due to the above, in this work, a comprehensive review of the literature was conducted, presenting the most relevant information on the possible molecular mechanisms by which mLOY is generated, as well as its implications for men’s health and its possible use as a marker to infer age.

Snipps from PDF

"Of these, tobacco smoking represents the major risk factor for aging-related mLOY [6]. Since the frequency of mLOY in current smokers is significantly higher than that in former smokers [30,31], the effect of tobacco smoking on mLOY appears to be reversible"
"In addition, several other environmental factors, such as polycyclic aromatic hydrocarbons, air pollution, heavy drinking, and obesity, have been linked to the risk of mLOY."

Related on web with FREE PDFs

Loss of the Y chromosome in coronary artery disease - Editorial May 2025 FREE PDF
Somatic Loss of the Y Chromosome and Alzheimer’s Disease Risk - Jan 2025 FREE PDF. doi: 10.1002/alz.090093
Mosaic loss of the Y chromosome and men's health - Feb 2022 FREE PDF "Accumulating evidence suggests that mLOY represents the most common acquired chromosomal alteration in humans, affecting >40% of men over 70 years of age."
Mosaic loss of Y chromosome and the association to mortality in Danish men aged 56–100 years - Dec 2024 FREE PDF
- The proportion of men with mLOY increases until age 85 years and then plateaus.
- mLOY increases with age, although with substantial inter-personal variation.
- The broad-sense heritability of mLOY in Danish 70+ year-old men is 72 %.
- mLOY associated with mortality in all study participants and in men below 80 years.
- mLOY associated with better survival in centenarians, likely due to selection.