Say that you slip with the knife while cutting up an apple for lunch. Ouch. It may bleed a bit, but you know that pretty soon it will stop.
A whole cascade of events takes place to form a blood clot. The ITGB3 gene codes for the fibrinogen receptor that is a part of how platelets form clots. This clotting action vitally important when you cut yourself — but clotting too much or too quickly can also be a problem for heart attacks and strokes.
There are hundreds of studies on the ITGB3 genetic variant known as PIA1/A2. Here is an overview of some of the findings:
While this genetic variant does seem to increase the risk for various cardiovascular events, keep in mind that it is probably acting together with other genes, gender, and environmental factors.
Most genetic variants that have a ‘down’ side also have an ‘up’ side. There is a reason that they are still prevalent in the population. The downside of the A2 variant here is obvious – increased early heart attack deaths without modern medical care. If people carrying this ITGB3 gene variant died from early heart attacks, at some point the variant should have dwindled out in the human population. Instead, there is a positive reason that it is still in the population – and this is due to protection from dying from contagions that cause excessive bleeding.
A new study shows that carriers of the A2 variant are protected from getting the hantavirus. The hantavirus is spread in mouse and rat feces, and, in Chile, it has a mortality rate of 30-35%. The virus causes cardiopulmonary responses due to increased vascular permeability. The study found that those people carrying the A2 variant were less likely to get the hantavirus. The study looked at both people who got the virus and people exposed to the virus who didn’t get it. None of the hantavirus patients (n=74) carried two copies of the variant. In the group that was exposed to the virus (n=105) but didn’t get sick, 11% of them carried two copies of the variant. [ref]