A recent study showed a potential link between the X chromosome inherited from mothers and accelerated brain aging, which could increase the likelihood of conditions such as Alzheimer’s disease. Conducted by researchers at the University of California, San Francisco (UCSF), the findings shed light on how genetics may influence cognitive decline, particularly in women.

What is the X chromosome’s role in brain health?

The X chromosome carries a great deal of genetic information and plays a very important role in general brain health. Females inherit two X chromosomes-one from each parent. Males, on the other hand, inherit one X chromosome from their mother and a Y chromosome from their father. However, in females, one of the X chromosomes is randomly deactivated in each cell, which results in variable effects.

“Given the fact that the X chromosome is enriched for brain-related genes, it became very important for us to know what roles it might be playing in brain aging,” explained Samira Abdulai-Saiku, a UCSF postdoctoral fellow and the study’s lead author.

Impact of maternal X chromosome

The researchers performed experiments on female lab mice of different ages. In some experiments, they silenced the paternal X chromosome and let only the maternal X be active. These mice were compared with others that had both maternal and paternal X chromosomes active.

The results showed major differences. While young mice with only the maternal X chromosome active ("Mom-X mice") performed similarly to their peers, older "Mom-X mice" exhibited some cognitive decline. This decline was linked to accelerated biological aging in the hippocampus, a key brain region responsible for memory and learning.

“These findings raise the possibility that some women who express more of their mom's X chromosome just by pure chance may have more cognitive impairment with aging or an increased risk for diseases like Alzheimer’s,” noted Dena Dubal, the study’s senior author.

What do these finds mean for humans?

Although the research was conducted on mice, the implications for humans are huge. If these findings could be applied to humans, it would reveal the sex-specific drivers of brain aging and cognitive decline. It may eventually open the door for targeted treatments or preventive strategies against diseases like Alzheimer's.

“Ultimately, it could also help us find constructive strategies for slowing brain aging in both sexes,” added Dubal.

This study contributes to a growing group of research efforts that emphasize genetic contributions to healthy brain aging and cognitive decline. While much more work has to be performed to confirm findings in humans, these results show promise for combating cognitive decline and conditions associated with neural aging.