A study from the University of Maryland published in 2022 found a relationship between the A1 subgroup gene and early onset of stroke. Among the most well-known blood types are A, B, AB, and O. Within them, there are multiple variations derived from mutations in the responsible genes. This study gathered data from 48 genomic studies, which included 17,000 with stroke and 600,000 without stroke, all between the ages of 18-59.
The second analysis showed that people who had a variation of blood type A faced a 16% higher likelihood of having a stroke before turning 60 compared to the other blood types. In the case of group O1, the risk was not only low but 12% lower. As Steven Kittner from the University of Maryland explains, it is still unclear what condition related to blood type A is responsible for causing a higher risk. It is believed to be related to coagulation factors, such as platelets.
They also determined that cardiovascular accidents that occur early in life function differently than those that occur later. Other studies have shed light on these unknowns, suggesting that the part of the genome that encodes blood type – ‘ABO locus’ – could be associated with coronary artery calcification. The study, which was published in Neurology, has also determined that the genetic sequence for blood types A and B is also related to a higher risk of suffering from venous thrombosis.
Blood groups
Blood groups are the classifications of the different types of blood that can be found in humans. They are based on the presence or absence of antigens on the surface of red blood cells, and being aware of one’s own blood group is essential to avoid immunological reactions and to perform safe blood transfusions. The two main systems are the ABO and Rh, resulting in a list of group A, B, AB, and O.
Genomic studies
There are many genomic studies that have been carried out throughout the history of medicine, with varying degrees of success. The second case is the one conducted by genomic researchers at the University of Maryland, who obtained significant data, which was published in 2022 in Neurology. The study shed light on the relationship between the A1 subgroup gene and the early onset of stroke.
With a sample of 17,000 people who had a stroke and 600,000 who did not, they gathered data from 48 genetic studies of individuals aged between 18-59 years. The first analysis resulted in the assertion that the location of blood type genes is related to an early risk of stroke. After the second analysis, the conclusion was that people with a variation of blood type A had a 16% chance of suffering a stroke before turning 60, while those with group O1 had a 12% lower risk.
What do the researchers say?
According to Steven Kittner, lead author and vascular neurologist at the University of Maryland, “We still do not know why blood type A might confer a higher risk. But it is likely that it has something to do with blood coagulation factors such as platelets and cells that line blood vessels, as well as other circulating proteins, all of which play a role in the development of blood clots.” Another finding was related to strokes occurring before and after the age of 60.
With a sample of 34,300 that included individuals over 60 who had suffered a stroke and those who had not, they determined that cardiovascular accidents that occur early have a completely different functioning. This is because in young people, they are often related to the formation of clots. Previous studies have also shed light on the ‘ABO locus’, the part of the genome that encodes blood type, which has been associated with increased coronary artery calcification and with heart attack.