Sex & Aging: New Disease Insights
- A new study from the Technical University of Munich (TUM) suggests a novel reason why women and men experience aging differently.
- Females possess two X chromosomes in each cell, while males have one X and one Y chromosome.
- "We have now shown for the first time that with increasing age, more and more genes escape the inactivation of the Barr body," said Dr.
The latest research unlocks new insights into why women and men age differently. A study on female mice, published in *Nature Aging*, reveals that genes on the typically inactive X chromosome reactivate with age, possibly influencing sex differences in age-related disease and women’s health. This could be a key factor in understanding conditions like cardiovascular disease and neurodegenerative disorders. Scientists discovered that with increasing age, more genes escape inactivation of what is called the Barr body. This finding offers new perspectives, moving beyond solely hormonal explanations. News Directory 3 provides the most up-to-date information on scientific breakthroughs. Furthermore, ongoing research will focus on confirming these findings in human studies. Discover what’s next for women’s health.
Silent X Chromosome reactivation May explain Aging Differences in Women
Updated May 27,2025
A new study from the Technical University of Munich (TUM) suggests a novel reason why women and men experience aging differently. The research, focused on female mice, indicates that genes on the typically inactive second X chromosome can reactivate with age. This process could influence women’s susceptibility to conditions like cardiovascular disease and neurodegenerative disorders, including dementia and Parkinson’s disease.The findings were published in Nature Aging.
Females possess two X chromosomes in each cell, while males have one X and one Y chromosome. To prevent an overabundance of X-linked gene products in females, one X chromosome is silenced, forming a compact structure called the Barr body. some genes, however, escape this inactivation.
“We have now shown for the first time that with increasing age, more and more genes escape the inactivation of the Barr body,” said Dr. Daniel Andergassen, group leader at the Institute of Pharmacology and Toxicology at TUM.
The researchers discovered that in older mice, the proportion of reactivated genes was, on average, twice as high as in adult animals. Specifically,6% of the genes on the X chromosome were reactivated in older animals,compared to 3% in adults. In organs such as the kidneys, the number was even higher, reaching nearly 9%.
First author Sarah Hoelzl explained, “With aging, epigenetic processes gradually loosen the tightly packed structure of the inactive X chromosome. This mainly happens at the ends of the chromosome, allowing for genes located in those regions to be read again.” This reactivation of the silent X chromosome could be a key factor in understanding sex differences in age-related disease,offering new insights into women’s health.
Many of these reactivated genes are linked to disease.Andergassen believes the findings in mice may translate to aging women, given the similarity of the X chromosome between species.The impact of these reactivated genes on disease growth requires further examination. The researchers suggest that this doubled gene activity could have both positive and negative effects.
For instance, ACE2, a gene that escapes inactivation in the lungs with age, can help limit pulmonary fibrosis. Conversely, increased activity of the TLR8 gene in old age may contribute to autoimmune diseases like late-onset lupus.
“Sex differences in age-related disease are incredibly complex,” said Andergassen. “So far, scientific explanations have mostly focused on hormonal or lifestyle factors…the finding that many genes on the inactive X can reactivate with age opens up entirely new lines of research.”
What’s next
Future research will focus on confirming these findings in human studies and determining the precise effects of reactivated genes on the development of various diseases. This work could provide an option to hormonal explanations for sex differences in aging and perhaps contribute to understanding why women statistically live longer.