Aortic dissection is a disease where the aorta splits in between its many layers and creates another channel. This results in a weak aorta that ultimately leads to the aorta bursting under pressure. This is always fatal if not caught beforehand. The defect usually occurs due to a genetic defect in the protein fibrillin.
Due to a compromised structure of the protein, the aorta is unable to withstand the high pressures that leads to the wall splitting and resulting in the formation of a dissection. Such patients often have other symptoms as well that point towards defective protein structure and hence the protein.