A stroke occurs when blood flow to the brain is interrupted or blocked. A lacunar stroke is a type of ischemic stroke that occurs when blood flow to one of the small arteries deep within the brain becomes blocked. According to the National Institutes of Health, lacunar strokes represent about one-fifth of all strokes. Damage to the blood vessels and interruption to blood flow can lead to long-term disability, causing difficulty with thinking, memory, and can lead to dementia. The genetic basis of lacunar stroke is poorly understood. Now, scientists report they have uncovered genetic clues to lacunar stroke.
Their findings are published in The Lancet Neurology in a paper titled, “Genetic basis of lacunar stroke: a pooled analysis of individual patient data and genome-wide association studies.”
“Despite the public health importance of lacunar stroke as the cause of a quarter of all strokes, previous GWAS studies have only identified one genetic locus associated with the disease, in contrast with the 35 identified for ischemic stroke and its major subtypes,” wrote the researchers. “We did a GWAS of lacunar stroke, including the largest number of cases with MRI confirmation to date, identifying 11 novel loci in addition to replicating the one previously reported locus.”
Researchers scanned and compared the genetic code of 7,338 patients who had a lacunar stroke with 254,798 people who had not. The patients who were scanned were from Europe, the United States, South America, and Australia after they attended the hospital and had an MRI or CT brain scan.
The genetic changes are thought to make the small blood vessels “leakier,” causing toxic substances to enter the brain, and meaning that messages traveling around the brain slow down or don’t arrive at all.
The researchers are looking forward to testing whether new treatments can correct these abnormalities on brain cells in the lab. They hope they can work on clinical trials in the next ten years.
“These small and often silent lacunar strokes have gone under the radar for a long time, and so we haven’t been able to treat patients as well as we’d like to,” explained Hugh Markus, PhD, BHF-funded researcher, leader of the study, and neurologist at the University of Cambridge. “Although small, their consequences for patients can be enormous. They cause a quarter of all strokes and they are the type of stroke which is most likely to lead to vascular dementia.”
“We now plan to use this new genetic blueprint as a springboard to develop much needed treatments to prevent lacunar strokes from occurring in the first place and to help stave off dementia.”
“Genetics offers one of the few ways we can discover completely new insights into what causes a disease such as lacunar stroke,” added Matthew Traylor, PhD, first author of the study at Queen Mary University of London. “It is only by a better understanding of what causes the disease that we will be able to develop better treatments.”
These findings provide hope for the future of preventing and treating these types of strokes.