Source: NHGRI

Researchers at Edith Cowan University (ECU), Australia, have identified a genetic variant that could link poor sleep to a person’s risk of Alzheimer’s disease. The study, which was published in Translational Psychiatry today, demonstrated that people with certain variants in the gene that codes for Aquaporin-4 (AQP4) suffered from both poor sleep and a build-up of beta-amyloids in the brain, a key feature of Alzheimer’s.

Poor sleep has been recognised as a symptom of Alzheimer’s for some time, but more recent research has suggested that it may in fact be a risk factor in the condition.

“The initial thought was that poor sleep was a result of Alzheimer’s disease but now we know that this is what we call a bi-directional relationship; that sleep may impact on the risk of Alzheimer’s disease and then as one develops Alzheimer’s disease it impacts upon sleep patterns, a bit like a vicious circle in a kind of a way,” said Simon Laws, PhD, lead author and Associate Professor and Head of the Collaborative Genomics group at ECU’s School of Medicine and Health Science. “For the first time, we’ve found that people with genetic variants in AQP4 who also have problems getting to sleep and sleep for shorter periods have high levels of beta-amyloid in the brain.”

The study involved examining data from a large cohort of participants from the Australian Imaging Biomarkers and Lifestyle Study of Ageing. In particular, the team were interested in AQP4, a protein which is found in the brain and which is known to be important in the glymphatic system. The glymphatic system is a process that occurs while we sleep, and involves the removal of toxins such as beta-amyloids. It stands to reason, therefore that a break down in this system could be linked to an increased risk of Alzheimer’s.

To that end, the team compared participants’ AQP4 proteins with their sleep patterns. They found that individuals with particular protein variants who slept for six hours had high levels of beta-amyloids in their brain, whereas those with variants linked to eight hours or more of sleep had much lower levels.

“In some individuals, their glymphatic system may function perfectly well on six or eight hours sleep, but this study suggests that individuals with a genetic variation might need more sleep,” Professor Laws said.

More research into AQP4 is needed before any firm conclusions can be drawn, but this research suggests that sleep intervention could be a possible route for Alzheimer’s prevention.