A study published in the medical journal of the American Academy of Neurology, Neurology, has shown that people with a genetic predisposition to Alzheimer’s disease may have a higher risk of epilepsy. Equally, people with a specific type of epilepsy could have an increased risk of developing Alzheimer’s disease. The findings highlight a strong relationship between these two conditions and may help us understand better some of the common symptoms between the two diseases.
The study used gene variation throughout the human genomes of 111,326 people with Alzheimer’s disease and 677,663 people without the disease through what is known as a genome-wide association study. Such studies involve looking at long stretches of DNA to identify small differences in the genetic sequence between people with and without Alzheimer’s disease. Researchers used a study design called Mendelian randomization to determine if there was cause and effect between the genetic variations and the risk of epilepsy.
The team found that those with focal epilepsy, accounting for more than half of all cases of epilepsy, were more likely to develop Alzheimer’s disease. Researchers also discovered that those with Alzheimer’s had a 5.3% increased risk of generalized epilepsy, which involves seizures that occur from both halves of the brain. Additionally, focal epilepsy with hippocampal sclerosis was linked to the development of Alzheimer’s disease, with those with focal epilepsy having nearly four times the risk compared to those without epilepsy.
The study also analyzed the genes of 13,116 people who had data on the levels of a biomarker for Alzheimer’s disease called amyloid in their cerebrospinal fluid. Lower amounts of the biomarker indicate an increased deposition of amyloid plaques in the brain. The researchers found that genes that predicted a lower amount of the biomarker were linked to an increased risk of generalized epilepsy.
However, a significant limitation of the study was that participants were of European ancestry, which means that the findings may not be generalizable to people living in other countries and of different ethnicities. Further research is needed to evaluate the link between Alzheimer’s disease and epilepsy fully.
Understanding the link between Alzheimer’s disease and epilepsy is vital for effective treatment and management of both conditions. Clinicians who treat patients with either condition should screen them regularly for symptoms of the other and manage treatment accordingly. If caught early, patients with either condition could improve their overall quality of life and even slow down the progression of their disease. The discovery of the link between the two conditions may also lead to vital clues in understanding the underlying mechanisms of each condition. The study was funded by the Chinese National Natural Science Foundation and Zhejiang Province.
